Tamerlan and Dzhokhar Tsarnaev grew up in the United States before planting the bombs that killed three people and wounded hundreds at the 2013 Boston Marathon. Panorama reporter Hilary Andersson tracks down people who knew the brothers, piecing together how two young men educated in American schools moved toward violence, and what, if anything, could have flagged it earlier. She also rides along with the New York Police Department's anti-terrorist squad, watching the surveillance technology and tactics built specifically to prevent another attack like it. That access cuts both ways: Muslim community members interviewed in the film describe those same programs as blanket profiling rather than targeted policing, and Andersson puts that tension to law enforcement directly. The film sits between two ongoing arguments, one about how radicalization actually happens inside families and communities that look unremarkable from outside, and one about whether counterterrorism surveillance is aimed at real threats or just at Muslim Americans. Dzhokhar Tsarnaev is awaiting trial as the film closes.