Meet the Ghost Sisters: Kat and Marie Bench. They love anything to do with ghosts and the supernatural. When their divorced mom moves them to her hometown in Colorado, the sisters discover a real ghost haunts their school-that of a young girl who cries, slams lockers, and leaves mysterious messages as floors writhe, walls weep, and a terrible accident is replayed. Armed with resourcefulness and ghost-hunting tricks they picked up from books and TV, the sisters set out to find the identity of the student apparition. Meanwhile, one of their friends is being bullied. Kat and Marie will need bravery and determination to help their friend and solve the mystery of the girl in Hallway B.