Grief has settled in at Hart House. For nine months, Alfie has been caring for his twin seven-year-old daughters after the sudden death of their mother, Pippa. One night, Alfie wakes to find Sylvie and Cassia at the foot of his bed, claiming there's a man in their room. Alfie finds no sign of a man, but it isn't long before the girls start talking about an imaginary friend. What seemingly begins as a harmless coping mechanism for the two grieving girls quickly develops into something more insidious.. Alfie calls upon Julia—Pippa's twin and a psychiatrist—to oust the malignant tenant from their lives, but he doesn't want to leave. As his malevolent grip on the girls tightens—with increasingly dark and violent consequences—Alfie and Julia must contend with their own unspoken sense of loss, the haunting past of the house itself, and the true character of the force that has poisoned the girls' minds.