One summer night, police discover the lifeless body of a young woman on an abandoned yacht. She appears to have drowned, but it's clear she was never in the water. The next day, a man is found hanging in his completely empty apartment. It seems like a suicide, but the circumstances are suspicious.
Detective Joona Linna is called in to investigate, and, with the help of a young Swedish Security Police detective named Saga Bauer, he soon discovers a surprising connection between the two deaths. With more lives at stake, Joona and Saga must fight to stop a killer who always seems to be one step ahead. Ultimately the case will lead them into the shadowy world of international arms trafficking, where they are forced to confront a ruthless psychopath.