Melanie and Kai take part in a raid on a café, without success as the Russian owner has obviously been warned at the last minute.  At the same time Boje and Franzi are called to the scene of a shooting.  A man has been targeted and murdered in cold blood shortly before he could disclose information about the Russian mafia to Volker Hillman, a official of the department for Organised Crime. The only witness: little Leonie, the daughter of one of Boje’s previous girlfriends. To Boje it’s immediately clear that the girl is in great danger. When Leonie’s mother, Antje is attached and badly injured by two men of the russian mafia, Boje has to promise to ensure Leonie’s safety under all circumstances. But how did the men know so quickly where the witness was hiding? Boje has a terrible suspicion. The leak has to be within the police force itself…