Olivia (Troian Bellisario) and Matthew Grey (Tom Felton), are 18-year-old twins born into a world of privilege and high expectations. There are almost no boundaries between them; even their dreams are connected. As the twins prepare for their last year of school together, an unexpected tragedy splits them apart, leaving the one survivor to learn how to live without their other half - or test how far they are willing to go to bring them back.

Teenager Ethan Wate is obsessed with his urge to finish high school and go on to college in order to leave the small town of Gatlin, South Carolina behind, until a mysterious girl begins to inhabit his dreams. When he meets Lena Duchannes, a newcomer who has just enrolled in his school, Ethan knows she is the girl in his dreams. Lena is rejected by the rest of her classmates for being the granddaughter of Macon Ravenwood, whom the town's superstitious residents consider to be a devil-worshiper. But Ethan gives her a ride anyway and they fall in love. Lena reveals to her new boyfriend that she is a witch, and that on her sixteenth birthday she will be claimed by either the forces of light or of darkness. She will remain in the light, but only if she does not remain in love with Ethan. To make matters worse, her evil mother, Sarafine, is casting spells to push Lena to the dark side. Ethan joins her in a search to find a magic spell to save their doomed love. Will the lovers succeed?