With a dog tattoo on his neck and puncture wounds on his back, private detective Peter Mang is found half-naked in a pit. Has he become the victim of his secret investigations? The trail leads Inspector Thiel to the villa of the industrialist family Rummel. Despite the clean facade, Sabine and Markus Rummel's marriage seems to be crumbling: After all, the photos taken by the detective show that the works manager and his new assistant Christine Schauer have more in common than just an employment relationship. The private detective was hired byAlfred Weskamp. The former works employee is an older friend of the Rummel family. Wesskamp also reveals to Inspector Thiel that the company under the leadership of Markus Rummel has recently got into financial difficulties. Meanwhile, Prof.
Boerne is once again investigating on his own. The fact that the murdered private investigator looked so similar to him doesn't let the forensic doctor go. The dead man's conspicuous tattoo leads him to a relevant tattoo studio in Münster. Here he meets the Belarusian Jan Sievic - and his attack dog...