Ava and Kaye used to be best friends. Until one night two years ago, vampires broke through the magical barrier protecting their town, and in the ensuing attack, Kaye’s mother was killed, and Ava was turned into a vampire. Since then, Ava has been trapped in her house. Her mother Eugenia needs her: Ava still has her witch powers, and Eugenia must take them in order to hide that she's a vampire as well. Desperate to escape her confinement and stop her mother's plans to destroy the town, Ava must break out, flee to the forest, and seek help from the vampires who live there. When there is another attack, she sees her opportunity and escapes.

Kaye, now at the end of her training as a Flame witch, is ready to fulfill her duty of killing any vampires that threaten the town, including Ava. On the night that Ava escapes, Kaye follows her and convinces her to travel together into the forest, while secretly planning to turn her in. Ava agrees, hoping to rekindle their old friendship, and the romantic feelings she'd started to have for Kaye before that terrible night.

But with monstrous trees that devour humans whole, vampires who attack from above, and Ava’s stepfather tracking her, the woods are full of danger. As they travel deeper into the forest, Kaye questions everything she thought she knew. The two are each other's greatest threat—and also their only hope, if they want to make it through the forest unscathed.