A sleep-deprived young man's life spirals into a nightmare when a mysterious old man begins scraping his fifth-floor window at 3 AM every night. The stranger begs to be let in, using lies and pity as his keys. But when the man vanishes into thin air, the chilling truth is revealed: he isn't human. Now, the nightly visitor is escalating its psychological torment, and the only barrier between life and a hungry, ancient entity is a single pane of glass. He must uncover the building's dark history before he makes the fatal mistake of letting it in.