Three nocturnal knavish drunk intruders in the Stuttgart Natural history museum find the corpse of scientific staffer Dr. Markus Fink, fatally stubbed with an exhibited narwhal horn. Fink had an affair with his director Dr. Ulrike Plöger, but also rivaled her as better curator. IT-er Rico Sander finds a security video of Fink rowing with devoted, retired voluntary museum guard Ferdinand Horch, who claims it was just about his 'unqualified' tour guidance, which Ulrike Plöger welcomes. Markus Fink also was intimate with biology student and museum cashier Agnes Försching, who discovered her mentor's doctoral study is mostly plagiarized, yet denies blackmail. Arnaud discovers a rhino horn was swapped with a plaster fake, good enough to come from the museum's own workshop, and sold as 'Chinese traditional medication'. Precinct evidence room officer Friedemann Sonntag, who came to arrange the team building trip to the museum, stumbles upon a clue to link both crimes.
—KGF Vissers