Sam Maddox, a girl grappling with her father’s suicide, has gained a reputation at her high school for her somewhat promiscuous behavior. When she starts dating the exceptionally intelligent Henry Sinclair, who is on his way to MIT, their unlikely pairing sparks a strong attraction. Unbeknownst to Sam, Henry is consumed by a dangerous romantic fixation and is willing to eliminate anyone who threatens their ill-fated and increasingly lethal relationship.