The latest trailer for the upcoming thriller American Assassin tells more of the true story about a college student who trains to be an efficient assassin.

Based on the book, Dylan O’Brien plays Mitch Rapp, an unassuming college student who suddenly finds himself thrust into the world of spies and assassins after he sees his fiancee killed in a terrorist attack.

Grief-stricken and wanting payback, he is recruited by CIA deputy director Irene Kennedy (Sanaa Lathan) and sent to train with Cold War veteran Stan Hurley (Michael Keaton), who would be the most feared training officer in the CIA if more than a handful of people at the agency actually knew of his existence.

American Assassin opens September 15.