She seemed to have no body. She thought she might be a ghost. She did not even know her name. All she knew was that she was one of four sisters whose parents ran a boarding house in a boys' school -- but whether she was fat Cart, morbid Imogen, almost-normal Sally, or strange Fenella, she had no idea. Only one thing seemed clear: Her peculiar state had "something to do with Monigan, the goddess Cart had invented a year ago.

The ghost tried desperately to let the sisters know she was there. She tried to tell boys from the school and to attract her parents' attention. For a long time nobody noticed her except Oliver, the dog. When the sisters did notice her, they tried to deal with her in all sorts of ways, and nearly everything they did got someone into bad trouble.

In fact it took a lot of trouble before everyone realized that Monigan was a real goddess, terrible and threatening, and that the ghost was somehow in her power. And it took a sacrifice from everyone before the ghost could discover who she was. But saving her from Monigan would be even more difficult.