Deadbolt (2024) Plot Summary & Ending Explained

Amelia finally pieces together the true source of the house’s terror. The strange noises, the missing medication, the rash‑inducing face mask and the secret attic hideout are not the work of a wandering spirit but of David, the quiet neighbor who had seemed like a perfect match for her. He is the surviving son of the abusive couple who once lived there; after his mother’s murder he grew obsessed with protecting the house and, twisted by guilt, began “guarding” anyone who moved in. David had been living in the attic, stealing Amelia’s anxiety pills, sabotaging Melinda’s skincare routine and even manipulating events so that her ex‑boyfriend Colin would return, only to be killed when David struck him down.

When Amelia confronts David about the attic and the evidence she finds – Melinda’s purse, a discarded sodium bottle and his unsettling knowledge of private conversations – his façade crumbles. He admits the murders of Melinda and Colin and reveals that he had been steering the police toward the wrong suspect. In a desperate fight for her freedom, Amelia calls the authorities and, in a burst of defiant courage, hurls David out of the window, where he lands in a dumpster below. The police arrive, take him away, and the lingering threat finally ends.