A German tourist photographs young men in Vienna's city centre. One of them, the handsome Hubert Meixner, he invites to his hotel room in the evening. The next morning, the tourist is found dead – the photos are the only trace. When Hubert Meixner wants to pick up the pictures, he is followed by Commissioner Moser and Rex. But he has a watertight alibi for the time of the crime. Only one can help: Max Koch. While he investigates undercover with Rex, Moser and Stockinger examine the photos. The trail leads to the Volksgarten. With Rex's help, Moser comes to the connection between the photos and the motive for the crime. Also privately there is some excitement: Moser and Rex move into the new house and Moser makes an appointment with the veterinarian Dr. Koller. Rex doesn't like that at all...