Ethan Wate is a high school student living in a small town in South Carolina. He dreams of leaving his boring hometown and sees Lena Duchannes, a new student who recently moved to town, as his ticket out.
Lena is different from the other students at school, she's quiet and reserved, and seems to be hiding something. Ethan is drawn to Lena's mystery and they quickly become close friends, but he soon discovers that Lena is a witch.
As Lena's 16th birthday approaches, she will either become a powerful force for good or a dark evil that will threaten everything in its path. Lena's family, known as "casters", is divided between Light and Dark magic, and Lena must choose which side she will join.
Ethan and Lena fall in love, despite the warnings of their families and the town that wants to separate them. Ethan is determined to help Lena make the right choice, and fight against the forces that want to use her power for their own gain.
As the race to Lena's 16th birthday heats up, Ethan and Lena must protect their love and avoid the dangers that threaten their lives. They must also navigate the complicated world of magic, with its own rules and repercussions for their decisions.
In the end, Lena must decide which path to follow, and Ethan must decide whether to stay with her no matter what. Their love will be tested and their choices will be permanent, but they both know that they were meant to be together.