Gruff American gangster Dickey pushes his broken-down car along a causeway through rising seawater while his eccentric companion Albie lies inside, bleeding from a gunshot wound after a bungled robbery. Cut off by the unexpected rising tide, they are on the only road to a bleak and remote tidal island (Lindisfarne in Northumberland), where, in a dark castle on a hilltop, a deeply neurotic and effeminate middle-aged Englishman named George lives with his promiscuous young French wife Teresa. Dickey disconnects the phone lines and proceeds to hold the two hostage while awaiting further instructions from his underworld boss, the mysterious Katelbach.