On February 28th 1986, Swedish Prime Minister Olof Palme was shot in the back at close range while walking home with his wife from a cinema. He was pronounced dead on arrival at the hospital 10 minutes later. This was the beginning of the largest police murder investigation ever conducted in Sweden, and the case still remains unsolved.
During a particularly sunny August evening, Carol is approached by a mysterious man who wants her help. Carol declines, since the man doesn't want to reveal his identity. The next morning, the body of the man is found floating in the Norrkoping River.
Carol decides to determine why the dead man wanted to hire her. After discovering several connections between him and the murder of Olof Palme, she soon finds herself in deadly danger.