Introverted, melancholy Michael lives a quiet life with his compassionate, concerned mother. With no friends, his life outside his home consists of only his job as the custodian of a slowly decaying building in downtown Pittsburgh. It is a lonely, tedious occupation but one that suits him perfectly. He has his duties down to a science and is very proud of his performance.
One night his quiet, orderly world is turned upside down when a new tenant moves into the building. She is strange, mysterious, and disconcerting. She is a woman obviously hiding something evil.
As Michael slowly discovers the devious nature of her work and the sinister truth behind her skillfully crafted façade, his calm, organized world comes crumbling down.