When a pair of bright-but sociopathic teens conspires to commit the perfect murder, a troubled cop teams with her eager new partner to solve the case that left the community in fear and the police without a clue. High school ladies' man Richard Haywood (Ryan Gosling) and outcast Justin Pendleton (Michael Pitt) have no motive to commit murder, but they soon conspire to choose a random victim and pin the crime on local pot dealer Ray (Chris Penn), under the guise that the police will never suspect them of such a brutal act. Determined Det. Cassie Merriweather (Sandra Bullock) is assigned to the case, and quickly becomes suspicious of the elusive teens despite the doubts expressed by her superiors and her lack of solid evidence. Soon entering into a dangerous test of wills with the increasingly desperate and dangerous teens, her investigation leads her down a disturbing path that will test her skills as a detective and her will to survive.