As Halloween approaches, twin sisters Lark, who is alive, and Wren, a tethered spirit, find themselves drifting apart. While Lark is happy with new boyfriend, Ben, Wren is still hurting over her own still-alive-and-kicking love-interest, Kevin, who may or may not have kissed another girl. Spending more time on the Other Side and less time with her sister in the land of the living, Lark becomes close with the spirit of a young man, Noah, who was killed years ago. But Noah is not as nice as he seems, and his thirst for vengeance has a dark and sudden influence on Wren. With the veil between the worlds thinning for Halloween, the spirits are getting stronger and it will be up to Lark and her friends to stop Noah and save Wren from becoming a monster. But the only way to do that could be to destroy the boy that Wren is falling in love with.