"No, my wife didn't kill herself," says the man to private investigator Steffen Horndeich. He and his partner Jana Welzer investigate the case. But forensic medicine has no doubt: suicide. There is no evidence of murder anywhere in the deceased's immediate environment. But a few days later, her sister is shot dead. And so the investigators slowly begin to doubt that it was suicide. Then: another murder! With the same weapon - but on Mallorca. While the police are still debating who is responsible, Horndeich and Jana take the case into their own hands. Because the truth is much more far-reaching than they realised ...