Billy Bean lives alone in the small attic apartment of an unoccupied old mansion. His cheap rent is subsidized by an agreement to watch over the place while the owner is away. A bank teller and chronic introvert, Billy’s life is one boring, mind-numbing day after another. Since the age of four, at the exclusion of all the normal social interaction of activities other children his age enjoyed, he worked toward becoming a concert pianist. But, at age 18, after the horrific death of his father and then a rejection from the San Francisco Music Conservatory, Billy had plunged into a deep depression. He no longer felt the passion, the drive, or the need to play the piano, so he quit.

During his weekly inspections of the old mansion, Billy discovers a treasure, a beautiful Steinway concert grand piano. He is so inspired by the magnificent instrument that he tentatively begins playing again, but there is a slight catch. Each time he plays this marvelous piano, he hears an imploring voice inside his head. The mysterious voice compels Billy to visit psychiatrist, Abigale Applebee, who agrees to help him sort out what kind of mental health problem he’s experiencing. They soon discover the voice is not the result of a psychosis, but rather something far more sinister. Led by the voice, Abby and Billy unexpectedly uncover the horrific secrets of a long-forgotten cellar below the house. But who is going to believe them?