London. The late 1960s. It's Christmas and Jack Carter's the top man in a crime syndicate headed by two brothers, Gerald and Les Fletcher. He's also a worried man. The fact that he's sleeping with Gerald's wife, Audrey, and that they plan on someday running away together with a lot of the brothers' money, doesn't have Jack concerned. Instead it's an informant - one of his own men - that has him losing sleep.