Fourteen-year-old Ty and his mom, Nicki, live in London — until Ty witnesses a murder committed by his friend Arron and commissioned by gang members. When Ty tells the police what he saw, they suspect he’s in danger. Even as Ty and Nicki rush home to pack their belongings and enter the witness protection program, someone bombs their building.
Several officers oversee their relocation. An officer named Doug is assigned to check in on them, while Maureen gives them makeovers to disguise their appearances. Ty, who has been renamed “Joe,” likes his darker hair and colored contacts. As Joe, he finds that girls pay attention to him. He even starts dating Ashley, a popular girl with a reputation for being loose. He begins training as a runner, coached by a wheelchair-bound, Paralympics athlete named Ellie. He’s given a special gym access pass, which causes another boy (Carl) to bully him, perhaps out of jealousy. Meanwhile, Nicki is not happy with her frumpy new look and becomes depressed. She gets drunk and nearly burns down their apartment by letting a lit cigarette fall onto the couch. Ty begs her not to get them relocated again.
Ty learns the gang looking for him has beaten up his grandmother (Gran). The police sneak Nicki out of her relocated life so she can stay at the hospital. Maureen stays with Ty. When Carl and his friends nearly drown Ty during swimming class, Ty defends himself and ends up breaking Carl’s nose. After temporary expulsion, Ty is allowed to return to school and must train alongside Carl as punishment. Ashley breaks up with Ty after he pulls a knife on some boys who follow them while they’re at the park.
At a party at Ellie’s, Ty accidentally walks in on his classmate Claire cutting herself. Claire is Ellie’s younger sister. They begin to talk and develop a friendship. He promises not to tell her secret if she’ll keep his. Then he tells her who he really is and how he was involved with a murder.
Ty is finally allowed to visit Gran. The police sneak him out at night. His presence, along with his recitation of the rosary, brings Gran out of her coma. As Ty leaves the hospital, police catch a gunman and move Gran to another location.
Ty and Nicki attend another party at Ellie’s house. Ty hangs out with Claire, and Nicki makes out with Ellie’s trainer. Claire’s mother finds Ty and Claire together sitting in the dark and becomes concerned. Ashley, his ex-girlfriend, purposely humiliates Claire at school. Claire cuts herself and bleeds to the point of unconsciousness. Ty patches her up before the EMTs arrive, saving her life. But when Claire’s parents find out Ty knew about the cutting and remained silent, they refuse to let him spend time with her.
The police relocate Ty and Nicki, and Gran comes to live with them. Ty decides to admit the whole truth to Claire via email. The truth is that he was more involved with the murder than he told the police, and that he actually cut Arron with a knife to get his friend to leave the crime scene.