Convicted for a crime she didn't commit and haunted by mysterious Shadows, Lucinda Price is sent to Sword and Cross, an isolated correctional facility; there, she meets Daniel, who feels they've met before, and Cam, who knows why she's there.

Luce suspects Howson is controlling their memories and steals photos of her and others undergoing medical procedures; while on a hike, Howson learns of Cassie's attack and brings her to Sword and Cross.

Luce learns Daniel hasn't aged in over twenty years; determined to expose the truth, she plans a breakout with Daniel as proof; Howson is tipped off, and the Outcast injures Daniel; Luce finds the body of another Lucinda Price.

Miss Miriam hunts the Outcast while Howson fights to save Daniel; Luce and the others try to escape, but the creature pursues them; Luce learns who betrayed them to Howson and why; Daniel fades as he recalls a past life with another Luce.