|Publication date||February 11, 2014|
| Preceded by|
The Forgotten Ones
| Followed by|
Return to Paradise
I Am Number Four: The Lost Files: Fives Legacy was released on February 11, 2014.
In this exciting seventy-five-page prequel companion novella to the New York Times bestselling I Am Number Four series, discover the true origins of the traitorous Number Five. Before allying himself with the Mogadorians, before infiltrating the Garde, before committing the ultimate betrayal, Five was in hiding just like the others. But when his Cêpan dies, Five is forced to survive on his own. Eager to finally experience the world he was always kept apart from, Five soon gets involved with the wrong kind of people—the Mogadorians. In Five's Legacy see how one of Lorien's last hopes for survival became one of its most dangerous adversaries.
| Spoiler warning!|
This article contains plot details about the book.
Five goes to the beach clean himself up. He thinks about the only time they had encountered the mogs. It was when they were in Canada where Rey was Albert and Five was Cody. Rey pretended to be Five's grandfather. Rey had killed them and relocated them. They went around a lot and started to travel south when Rey's cough started. And they eventually settled in Martinique. When Number One died and Five got his first scar Rey was done with people and he sold all his possesions and brought Five to the secluded island they are living in. Sometimes Five pretends Rey is a crazy old man who kidnapped him from his loving parents. He thinks about the other garde and their Cêpans. He wonders if they are looking for him or not.
Rey calls for Five and tells him to kill the snake that has come close to the hog pen. Five hesitates and refuses. He tells Rey to do it instead. Rey is disappointed. He asks if Five can't kill a simple snake how he is going to fight an entire mog army. Rey kills the snake instead. Five runs away. Five is angry and the coconut in his hand bursts. He has finally developed telekinesis. He is excited but doesn't tell Rey. He instead trains with telekinesis alone. He decides to tell Rey about his newly developed legacy when he has mastered it in hopes of Rey will finally relocate them to somewhere more populated. He thinks he can easily fight mogs with his telekinesis. Rey now pops in random places around the island with his stopwatch to make sure Five is really doing his running making it diffucult for Five to find time to train his telekinesis in secret.
Five is becoming an expert and now he can lift trees. One day he trains for a long time and when he gets back he sees Rey lying on the ground barely alive. He carries him back to their shack. He sets him on the bed and sits in a chair next to him. Rey finally opens his eyes after a long time. He tells Five to survive and not to go find others until he is stronger. He dies. Five is sad, cries, and he regrets every bad thing he ever thought about Rey. Now he is all alone on the island. He buries Rey, and releases the hogs from their pen. Then he sets sail for Martinique-the island he formerly lived on with Rey. He is lost at sea for nearly ten days, until he developes his Flight which he uses to fly to Miami on accident. He ends up on South Beach where a woman jogger gives him water after seeing him fly. When a photographer arrives with a camera, Five ditches them and goes to a nearby park. After that, he goes to a fair where he steals a rich man's wallet with telekinesis. A police officer follows him, and Five escaped by flying on top of a building. Five spends the next few weeks doing everything he could not do on the island when Rey was alive. He goes to see movies, play games at arcades, and gains money by becoming a pickpocket. Soon, he meets a teenage girl named Emma. They become partners in crime and do a series of pickpockets. They meet Ethan after attempting to steal his wallet, and Ethan gives the pair a card, telling them to contact him. When they call him, they end up talking to someone else who knows Ethan. One day, after doing a series of errands for Ethan, he sends the pair to a warehouse to plant bugs. Five is ambushed by Ethan's goons and is forced to reveal his telekinetic power. Emma sees this, then is enraged when she recognizes her criminal brother-one of the goons who beat up Five. Emma strikes Five on the head with a pipe, and he passes out.
Five wakes up in Ethan's car. Ethan is beside him in the backseat, and one of Ethan's minions is driving the car. Five is driven to Ethan's mansion, where he lives with Ethan for awhile. He trains with Ethan, and lives in luxury. He also gains plenty of pounds-becoming chubby. One day, Five uses his telekinesis on a young guy when Ethan tells him to after the guy disrespects Five.
Five awakes one night, his calf burning. Three has just died. He is scared and decides to tell Ethan what he is. He goes to Ethan's top secret office where he sees a man talking to Ethan on a computer with pale skin and gills-a Mogadorian. Five freaks out, and Ethan stops the videochat. He tells Five that he has been working with the Mogs because he thinks the Loric don't stand a chance against the Mogadorian race. He also tells Five how he met Nine, and that Five would not like him if they ever met. Five later flies out the mansion where he discovers his Externa Legacy. He flies back towards the mansion, but crashes in Ethan's private beach. He morphs into sand, but Ethan and a maid are able to help him revert to his natural form. Five passes out after Ethan tranquilizes him.
Five wakes up in a bed inside the mansion. When he and Ethan talk again, Ethan manages to convince him to join the Mogadorians. They get in a helicopter where the pilot takes them to a FBI building that doubles as a Mogadorian base. Ethan is put in a different room, while Five is put inside a room where he talks to the Mogadorian that Ethan was talking to on the computer. The Mog praises Five, and tells him how they have another Garde in the building to test the charm on. Five agrees to ally himself with the Mogs, remembering Rey telling him to do everything he can to survive, which was his last words.
The Mog is happy with Five's decision, but tells him that he has to kill someone first. The Mog gives him a folder, that has the name and picture of the person he has to kill.
Five opens the folder, and the story ends there.