"But it's all a bit Grand Guignol, don't you think?"
U.S. Marshal's visit a secure psychiatric institution on an island when a patient escapes from a seemingly locked room. There are strange rumours surrounding the institute as well as water.
Gradually we find that one of the marshals has ulterior motives and that one of the patients is intimated involved in a tragedy from his personal life. It becomes clear that more is going on than first meets the eye.
