Alex Kerner's mother was in a coma while the Berlin wall fell. When she wakes up he must try to keep her from learning what happened (as she was an avid communist supporter) to avoid shocking her which could lead to another heart attack.

Whenever a criminal is killed in London, a black Jaguar is nearby, with a white cat always sitting in the passenger seat. Inspector Higgins and Inspector Lane find a joker card on all the victims. Their investigation leads them to a diamond smuggling ring.