Mosab Hassan Yousef is the eldest son of Sheikh Hassan Yousef, a leader of Hamas. He is caught running guns at 17 and imprisoned by the Israelis. He is shocked to find Hamas torturing people suspected of being informers. Israel's security service Shin Bet is able to recruit him and Gonen Ben Yitzhak becomes his handler.
I didn't know anything about this story before watching this movie. I honestly figured that this is a fictionalized account with actors for the first half hour. The style is very plain with Mosab and Gonen talking straight into the camera. The story is so compelling that it is utterly riveting. I do wonder why he did what he did. He gives explanations and hints but I'm not sure if there is something more.