Hailee Steinfeld (Romeo & Juliet), Jessica Alba (Spy Kids 4: All the Time in the World) and Thomas Mann (Prom) have signed on to star in the action-comedy Barely Lethal. Steinfeld plays Megan, a 16-year old whose been attending a boarding school that trains assassins. She just wants to be a normal teen so she fakes her own death and moves to a rural community, but then realizes she has no idea how to deal with high school. Mann plays her best friend who is secretly crushing on her. Samuel L. Jackson (The Avengers) will play her boss, the head of the assassin agency. Sophie Turner ("Game of Thrones") plays a secret agent who enrolls at the high school to try and kidnap her. It's unclear what role Jessica Alba will play. Brett Ratner is producing and Kyle Newman is directing the indie film.