Nellie Gomez is Dan, and Amy Cahill's au pair, and a Madrigal.
Nellie's father was from Mexico City and her mother from France, and the lived in the United States. She grew up trilingual, learning English, Spanish, and French. She took college classes with breaks in the summer, and her father wanted her to go to college very much. Her mom told her why Montmarte was called that, as a saint was killed on the hilltop. Nellie didn't like college, and also developed a 'working knowledge' of German, though knows most German.
Her parents always gave her flying lessons, defensive driving lessons, kung-fu lessons, and scuba diving lessons. She never knew that these were training regimens set up by Grace Cahill, as she was selected to be Amy and Dan's au pair. Grace grilled Nellie for hours for the job, and she accepted it. There was a catch, she needed to relay information to Fiske Cahill and William McIntyre about the kids.
Amy and Dan's great-aunt Beatrice Cahill was forced by Grace to hire Nellie to watch Amy and Dan. She made them waffles, and jammed to her iPod, and also texted a lot. One when Amy and Dan left to go to their grandmothers funeral, Nellie ate Dan's ice cream, and chilled out, listening to her iPod and texting. Amy and Dan shook her out of the iPod, and said they need Nellie to drive them around the world because they're going an annual 'scavenger hunt'. She promised more money, and that Nellie could get some food, or chill with the guys. Nellie accepted when Amy offered to sell her Grandmother's inherited jewelry. Nellie called her Dad, who yelled at her in rapid Spanish, but she decided to take the job anyway. Nellie booked them train tickets to Philadelphia and a car at a rental place at the train stop.
The next day, Nellie and the kids took the train in to Philadelphia and handed the kids a package from William McIntyre at the rental car place. It said to meet him at eight, and gave them a black light reader. They drove downtown in their Toyota Fusion, and Amy pointed out the Ned, Ted, and Sinead Starling following them, and Nellie flew through three lanes of traffic on I-95, going off and exit ramp. Nellie had to stay in the car with Saladin while Amy and Dan went into the Library Company of Philadelphia, founded by Benjamin Franklin. They came out, and rushed to the science museum and Franklin Hall, forcing Nellie to stay inside again, with Saladin. The museum then exploded and Amy and Dan ran in the car, Nellie telling them that she was going to call Beatrice, but Amy and Dan pleading her not to. They drove to Independence Hall, Nellie saying they should get back when her playlist's done. She got a voice mail from Social Service, and Nellie yelled at Amy and Dan when they came back from giving Saladin to Mr.McIntyre. Amy pleaded with Nellie saying it was very important, and Dan saying they're going to Pairs. Nellie agreed to take them to France.
On the flight there, Nellie had her headphone volume loud, flipping through French cookbooks with full-color pictures of snails and goose liver. In the terminal Nellie saw crowds swarming Jonah Wizard. Jonah saw them with Broderick Wizard and they escorted them to a limo. Jonah talked about his new album, Gangsta Life and Nellie told him she liked it, and Jonah told her to shut up as she wasn't a Cahill. Nellie stayed silent while Amy and Dan refused Jonah's offer to work together. Amy pulled over at a small hotel and the three got out. Amy told Nellie to get reservations as they went in pursuit of Irina Spasky.
Nellie stood outside the hotel for hours until late in the night Amy and Dan arrived. Dan told Nellie the whole story about the 39 Clues, Amy filling in, and Nellie decided to help them. Amy searched on the internet the Pairs Catacombs, and Nellie decided to go there, no matter what. They took the Métro to the Denfert-Rochereau station to get to the gate to the Catacombs, the Barrière d'Enfer. Nellie saw Alistair Oh and hit him, thinking he was a bad guy. Alistair told his story of the mansion fire and the Holts, and they decided to talk before going through the Barrière d'Enfe. They ate, Nellie ordering a gourmet dish, Alistair asking for 'insider tips' from Grace, and Nellie warned that he was too smooth. In the end they decided to go in the Catacombs alone, and Alistair saw Ian and Natalie Kabra, and went to stop them. All three slipped through the Barrière d'Enfer.
They started seeing bones from 1844, which was too recent, so they kept going into an unlit chamber, Nellie giving Amy her pin flashlight. They reached the bones from 1785 and began to look around, Dan seeing some numbered skulls. Looking at them, Amy realized it was a magic box, and clapping resounded. The Kabras held them at gunpoint, Ian asking for the magic box numbers, but Amy took a bone and resolved to crush the skulls. Before that, Alistair attacked the Kabras, Natalie's gun dropping out of her hand. Amy, Dan, and Nellie ran for hours, turning around and around until Nellie's flashlight went out. They heard a train, and moved toward the noise, emerging in a rail pit at a Métro station for express trains. They pulled themselves out, Nellie moving on the platform first, then Amy, but Dan's backpack was caught. Even though it had the only picture of Arthur and Hope, his parents, Dan left it, and was pulled up.
Amy, Dan, and Nellie went to dinner, and Dan figured out the magic box. Amy wondered if it was an address, but Nellie said it was probably different as Franklin made the clue in 1785. Amy decided they need a library, and the waiter directed them to Métro Line 8, and the station École Militaire. They then reached the American Library where the librarians gave them document lists, Nellie recognizing Iron Solute on the list. Amy found a map showing St. Pierre de Montmarte. As they walked up the Montmarte hill Nellie told Amy about the saint killed there. They passed the Sacré-Cœur Basilica and reached St. Pierre. Dan found a Lucian headmarker, and they dug in the pouring rain revealing an entrance in the Catacombs. They found a pitcher and a mural off Luke, Katherine, Tomas, and Jane, the founders of the family. They opened the jug and found an un-energized vial and sheet music. Jonah and Broderick Wizard came in, but Amy forced them to stand by Jane, threatening to smash the vial.
As soon as the three walked out, they saw the Holts van pull up. Trying to get away they opened the church door, running into Alistair and Irina. Eisenhower Holt threw a box of ice cream at the five, and it hit Alistair and Irina. Amy told Nellie to call the police and she and Dan entered St. Pierre. Nellie called the police, and when they arrived pointed at the church and Irina. Soon, everything was done, and they went to eat the next day on the Champs-Élysées where Amy said that the clue was an anagram, RESOLUTION all along. Dan solved it, the clue being IRON SOLUTE. William McIntyre came over, and they acted like the vial was the clue and the Kabras took it (the lie being it was the clue), and William nodded, giving them Saladin back. He left, and Amy produced the sheet music that their Dad played in his study, KV 617, Mozart's last chamber music. Amy said they needed to go to Vienna, where Wolgang Amadeus Mozart lived.
Nellie got a cheap and slow-moving train that in her words will stop in every 'podunk town in France, Germany, and Austria'. When the train stopped in Dijon, France the Holts entered the train and when Amy and Dan spotted them they ran while Nellie pretended to be a frenchwoman but Hamilton put her down, and they left. All seven came back, and Amy told the Holts that the music sheet was in the overhead. When it was opened, Saladin jumped out, the KV 617 sheet shredded. When questioned by the conductor, the Holts jumped out. At the Vienna hotel Nellie had to watch the un-eating Saladin while Amy and Dan were at the Mozarthaus. When they came back, they turned on the TV to see a Jonah Wizard press conference near the Mozarthaus. They then realized that Jonah's dad took Nannerl Mozart's diary, which was missing.
That night they snuck to the best hotel, and saw Jonah and his dad leave for a DVD release party. The three snuck in a worker-only door and Nellie changed into a uniform and getting a key card, Amy and Dan being hidden under laundry. They reached the royal suite, but a worker informed them the Grand Duke was in that one, not Jonah Wizard, but led her in, Nellie tossing her keycard to Amy and Dan in the cart. Nellie was scrubbing the Grand Duke's toilet when the guard said her nose ring was against policy, and not allowed so she couldn't work there. Nellie confessed she was trying to see Jonah in his suite when a crash came from below. Nellie was led down to see Amy and Dan run out, and before the guard could chase him, Nellie told him to look if Jonah was okay, but the guard said he was at a DVD release party, and the Vienna police arrested Nellie. The took a mug shot of her and then let her free, thinking she was just a deranged Jonah Wizard fan. So they wouldn't be lead to Amy and Dan, Nellie had them drop her off at the Hotel Weiner. She then walked back to Amy and Dan's hotel room where she translated Nannerl's diary from German, finding cuts made to it.
After discovering the message in the KV 617 sheet, Nellie got a Fiat from a rental car place, and drove Amy and Dan through the Austrian alps to Salzburg. On the streets Nellie almost hit Alistair Oh with the Fiat, and so began to trail his tour bus to the Abby Church of St. Peter. While Amy and Dan searched for the Clue, Nellie took Saladin to a vet for his compulsive neck scratching, finding an electronic homing device in the cats collar. Amy and Dan were half an hour late, and being chased by the monks for a parchment piece. Nellie translated the sheet, a recipe for Benedictine known only to the brothers for centuries. She then showed Amy and Dan the tracker and Amy got an idea of what to do with it. Nellie figured out where Alistair was staying, and they tailed him, Amy slipping the tracking device in his cane while he was dozing, and taking an old Italian Mozart promotional poster advertising a Venice appearance.
Nellie drove the Fiat, and they saw a Eurotainment TV van chasing a limo, and Nellie followed the chase, then the limo to the Venice parking lot where Jonah and his dad emerged. They barely made it to the ferry they were on, using Saladin to force them on. They followed Jonah to a CD shop where he vanished from view, but Amy and Dan couldn't search for secret doors with the cashier around. Nellie ran in and pulled CDs off the shelf, and told the cashier she was a kleptomaniac and ran with the CDs to create a diversion for the kids. She let some fall so they could be picked up. Hours later long after the store closure Amy and Dan arrived, drenched in canal water. Nellie got them a change of clothes.
They walked to the church where the Royal Saladin was docked, but it wasn't there and the missing Nannerl pages were in the seat cushion. They waited for three hours until it arrived with a wedding party which filed into the church. They took the Nannerl pages and went to the hotel where Nellie translated them. Nannerl talked about her brother's debt because Fidelio Racco had overcharged him for alloyed swords from Japan. The kids went to the mansion while Nellie stayed with a hungry Saladin who wouldn't eat cat food. Saladin tried it, giving into Nellie and quickly devoured cans of it. Amy and Dan came in with tungsten-alloyed samurai swords explaining tungsten or wolfram was the clue, and they needed to go to Japan where the swords were alloyed.
At the Venice airport they put the swords and Saladin on the luggage rack and went to the boarding station, where Nellie went on but Amy and Dan's passes were put in a routine check. After Nellie was on board she was joined by the Kabras. They asked her why Amy and Dan were planning to go to Japan, but Nellie gave sassy answers. She tried to ask the flight attendant for a restraining order, but the Kabras convinced her Nellie was crazy. Ian began to feel sick, so Nellie searched for an air sickness bag.
Natalie had put an entire vial of poison in Nellie's Coke, but she splashed it on the Kabras. She took the antidote, and the Kabras gave them their money for it. Landing in Tokyo, they saved Amy and Dan from a yakuza attack. They, and Alistar, work together. Finding a scroll with tOotA on it, Alistar deciphered it meant Korea. They chartered a plane to Seoul and go to Alistar's mansion there. Nellie laughed when a big dog, Buffy, bit Ian on the bottom.
Amy and Dan go to a place where the next clue is, and go back to the mansion. Nellie hugs them, but Alistar is dead. They find one of his gloves, meaning that he survived. They take a plane to Cairo, Egypt, because of the pyramids. Nellie meets up with Amy, Dan, and Theo Cotter, who met Amy and Dan. They took a cab to Sennari House, a Napoleon museum. Nellie was in the cab when the kids ran and jumped in, and they went to the Hotel Excelsior. They found a sheet of paper in French, that seemed to say the clue was in Paris.
They fake they're there under the Oh reservation, and get the huge Aswan Suite upstairs. Nellie began listening to her iPod. Nellie stopped and saw they were gone, and managed to get into the Ekaterina stronghold. There the kids were trapped in a glass box. Nellie put hummus on the crank, so Saladin would lick it to save the kids. They escape and meet Hilary Vale who drives them to her house. She shows the kids that she was Grace's friend, and gives them a letter from Grace. There is also a golden Sakhet statue.
Theo comes in, he's Hilary's son. He examines the Sakhet, and they find a letter written by Katherine Cahill, and a map. Comparing to maps found in the Ekat headquarters, they realize it's Queen Nefertari's tomb. While Amy and Dan leave with Theo to the Valley of the Queens, Nellie stays with Hilary. When they come back, they realize that Theo is trying to steal the Sakhet. Nellie stops him cold.
Nellie and the kids set Theo up to give a fake parchment to who he was working for, Irina. In Aswan, they go to a hotel room and find that Grace left them a painting pointing to an underwater island. They realize Alistar was bugging their room, and confront him. The kids and Alistar plan to go there. When they come back, they say that the underwater island was an outdated lead, and the real lead was a plant. mat 2:11. They realize that Grace left them clues about the Punt expedition and the Magi that visited baby Jesus. The Clue is Myrrh. Matthew 2:11 in the Bible. They go back in the Ekat stronghold, but find it destroyed. A cloth holds the culprit, a Madrigal destroyed the stronghold.
Nellie switches hotels, and the first night falls asleep to wake up and see Amy and Dan gone with her phone and money. She manages to call them several times, and they answer once, in St. Petersburg. Nellie takes a flight to Moscow, and meets Amy and Dan. They then take a flight to Sydney, where Grace's Ekat gem is stolen by an old lady. Nellie waties with Saladin outside a museum while the two go in.
They come out, Amy having encountered Isabel Kabra. Amy knows their uncle, Shep Trent, lives in Australia. The three go to Shep's house, and he apologizes for not staying in touch when Arthur and Hope died. Suddenly they are all called to the beach due to great waves. As they are learning to surf, the Holts try and capture them, but are knocked out by Shep's surfing buddies.
Back at Shep's, they find out that their parents went on a round-the-world trip to places in China and Indonesia, and stopped in Australia to see Shep. Shep agrees to fly them to Coober Pedy to search for Bon Troppo. Ian called Nellie, and he talked to Amy. Amy faked sickness, and they left her alone. She ran off, and later came back saying she'd met Irina and Isabel tried to kill her. Another paper found by Amy and Dan points that they're trailing Amelia Earhart who flew to Darwin. Shep will land in Coober Pedy to refuel, then go to Darwin.
They go to Coober Pedy, where most of the town is underground. They go to Ken, an old man who said that is father knew the silent Troppo, called him Fossie. Fossie lived in a depression in the opal mines. Nellie goes in with Amy and Dan, and they find Ring of Fire written everywhere and a volcano. Isabel drops a snake and spiders in the cave, but Shep bursts them out into Ken's room.
Using Dan's computer they search Robert Cahill, 1890's, Darwin. They come up with Bob Troppo, Robert Cahill Henderson. On the way to Darwin, they realize that Amelia Earhart really was investigating the Kraktau Volcano eruption. On the eruption day, a ship carrying tungsten and myrrh had to turn back from the Indonesian islands. In Darwin, Shep gets a plane to fly to Jakarta. Irina arrives to try and take the kids away, but Nellie sneaks them on the plane.
Apparently, Nellie can fly, and so she flies them to Jakarta. They eat at a hotel then, and Nellie falls asleep. She wakes to find them gone, and sees a message from McIntyre under the name clashgrrl. She realizes she needs to find Amy and Dan. Nellie calls the kids, and learns they're on Alistar's private Indonesian mansion. The boat arrives in the night, and Nellie waves at the kids. They just survived a fire that killed Irina.
Nellie has been followed by the police, and she gets off with Saladin. They go to a small cove where Irina's boat was and pull off to escape. Nellie is singing on her iPod when Amy and Dan confront her about the clashgrrl messages, and Nellie lies that she's her high-school friend. Dan says the words he found in Irina's notebook, and they're from a song that Nellie knows.
The police come closer and Arif, the pilot, gives up. Saladin is flung underwater, but is saved by Dan. They swim to the beach with the others, and Alistar takes the blame. Nellie says they need to go to Peoria, as that's the song lyrics. Amy goes to a library in Java, and learns that the song is about Pretoria South Africa, not Peoria Illinois. Nellie gets a cheap Yugo rental car, but the Holts are in a Hummer. They get in and speed to Pretoria.
They manage to lose the Holts in a goat field, but they hijack a farmer's purple pickup. Nellie drives the Yugo out of the way, and the Holts go to a soccer match. Hamilton sends Dan a message in Morse telling then to run when Alistar arrives. Amy and Dan choose to leave him with the Holts. Dan deciphers a postcard handed to them in the airport that names locations in Johannesburg. But first Eisenhower texts them saying Alistar will be blown up if they don't go to Boom Street.
They see Alistar rigged to an explosive device, and Dan manages to smash the van where the controls are so Hamilton can deactivate the trap. Nellie buys a new GPS she names Carlos, and they drive to Constitution Hill. Nellie stayed with Saladin at the hill's parking, and Amy and Dan came back with a Winston Churchill connection, which is to be explored at Witbank. They meet Kurt, and Amy thinks he's hot, and plays chess with him.
Nellie begins helping Dan into the old Churchill mine to look for what he left there. He gets a rubbing of Winston's message, and Kurt helps him out. He destroys it, and they drive off, and Dan re-writes it. He breaks the goad, and it says that the clue is at the coordinates given, Shaka Zulu's burial site. They briefly stop at a Shaka Museum, and apparently his shield with the Tomas crest was taken.
They go to the coordinates, and see a huge factory there. They try to get in, and are stopped by a guard, who lets them after they lie they're waiting for their parents. They find a Tomas clearance area, and find Irina had Tomas cards for them and fingerprints. They enter and meet Malusi, head of the Tomas stronghold. They go to a Shaka Zulu play, and Amy and Dan desert Nellie.
When they are gone, Nellie and Malusi look for them. They find them holding a box that they dug from Shaka's grave. Nellie joins the three, and they flee. They rush out and meet Professor Robert Bardsley, a Tomas operative working against them. He's there with Kurt and his singing group. The Tomas rush out and are lured into a huge hole. They open the box, learning the Clue is diamond.
At the airport they're going to Karachi in Pakistan, supposedly mentioned by Isabel as a place she thought Amy and Dan had been to. The Kabras capture them and try to force them to join the Lucian fold. When they refuse, Isabel begins to push a propellor to Amy to kill her. Bardsley saves them, and they get on the ''Flying Lemur'' to Mozambuique. Dan spills Kabra poison on him, and they go to Grace's house in Madagascar.
There they find an antidote and begin to apply it to Dan. Dan translates the Churchill note, that the Clue was aole, a healing herb the box was hid in. Dan reads a note about their parents in China, calling them M. Dan finds a composition, a Madrigal song. The last secret is that Amy and Dan are Madrigals.
They fly to London, and get on a flight to Beijing because their parents went there. Nellie watches Terminator Salvation on the flight. They find Alistair in the airport and send him packing. Amy leads them to the Gate of Heavenly Peace in the Forbidden City. Amy and Dan take a tour while Nellie waits for them. When they come out, Amy looks at a silk message. Dan runs away when she says maybe their parents were bad people.
At night, Nellie is calling Fiske or McIntyre when Amy interrupts her, scared. Nellie pretends she was calling Alistair to translate the Chinese, and then calls him. Alistair recognizes the seal of Puyi, Janus Qing dynasty emperor. There's also a poem there. Nellie and Amy go to a Jonah Wizard concert in Beijing, think Dan would be there. With a mass of screaming fans, they barely miss Dan by 10 seconds.
They meet Alistair again, and the newspaper says the next stop for Jonah is the Great Wall of China. Nellie and Amy decide to go. At the Great Wall, Amy tells Nellie that Puyi was the last emperor until 18. He even had a British name, Henry. They spend all day trying to find Jonah, but no luck. Once Saladin nearly falls off the Wall. They pay five-hundred yuan to get Saladin, and stay at a tiny hotel. Amy can't find anything.
Nellie decides to try the wall again, and they find a door with the Chinese character for Grace. Entering, Nellie and Amy go up some stairs to a locked door. Nellie picks it, and they find Puyi's feng shui puzzle. As Grace taught Amy feng shui, Amy reveals that Puyi's clue is on Mt. Everest. They need to take a train to Chengdu, which borders Tibet, because you need a permit to go into Tibet where Everest is. The flight goes to Chengdu where Nellie and Amy sleep waiting for their Tibetan permits. They come, and Amy and Nellie go to Lhasa airport in Tibet.
Amy tells Nellie they'll need to ride the A-Star, a ultralight helicopter that can land on Everest's summit. They run into Dan, who got on a Xian to Lhasa supply train. They meet the pilot, who refuses to take the A-Star up. Nellie calls McIntyre, and he yells at the pilot to convince him. Nellie waits with Saladin while Dan and Amy tackle the summit of Everest. They come back knowing silk was the Clue. They stay at a Tingri guesthouse where Dan reveals he found the remains of Gideon Cahill's lab equipment. He has a picture of Madeline Cahill, owned by Anne Bonny, pirate of Jamaica. They're going to the Atlantic.
At the airport in Beijing, the kids decide to go to the Bahamas. Nellie books them tickets there, and they give her the window seat on the plane. As she settles in, Nellie is grilled by the kids for her strange messages, and how she magically got Tibetan permits, and got them in the A-Star. She tells them that Grace had grilled her for the interview to be their au pair. Her other job is to give information to McIntyre about Amy and Dan, and if McIntyre tells other teams, that's his thing.
They arrive at their Bahamas hotel, and Nellie goes to the market. She gets exotic produce, and returns to where Dan is at the Oceanus theme park. They meet up with Dan, and get on a boat to a pirate cove. Nellie sees the kids, and they want to go in a cave. Nellie gets rope and ties it around her waist while they go in. She is met by Fiske Cahill who tells her that she can still get the money for keeping her working with Fiske secret. Fiske leaves when suddenly Amy is bleeding from the head, and she needs pulled back out. Nellie gives amy First Aid, and they turn the boat back to Oceanus.
They leave the hotel, and Dan tries to go after a calico cat. As they begin to go, a black SUV follows them, and a gray sedan follows them both. In Spanish Town, they meet
Nellie and the kids got from Cahill Island back to Ireland. With Alistar, they waited at the airport for their flight from Dublin to Boston. After the flight, Fiske became legal guardian of Amy and Dan. Nellie drove them to Hope and Arthur's grave, where they discovered a clue, and a code to the other. With the hunt over, Amy thanked her parents.
They later went to Grace's bank in Switzerland where the Vespers found them.