Nurse Maren Kranz is found beaten to pulp. The team finds she moonlighted as 'lure', test-dating the husbands of suspicious women who engaged her employer Monika Gerstenberg's agency to check their fidelity, like lately slick jeweler Henry Mengers. Kranz's roommate has a suspicious rapport to her. Timmermann and Lena go undercover to test the agency's real, devious activities.—KGF Vissers