Oops - here comes Britta Sander, a young detective on a turbulent murder hunt. At the Aachen detective agency Schniedewitz & Schniedewitz, everything continues as usual in its disordered manner: They observe truly or supposedly unfaithful spouses, try to convey the results to clients as gently as possible, and must ensure that boss Fritz Schniedewitz doesn't cause any trouble or actively interfere in an investigation. The colleagues, led by Britta Sander and Eric Lautenschläger, sweeten their dreary everyday life with small friendly pranks to keep their laughter muscles in shape. In the midst of this monotonous routine, the news breaks that career woman Sabrina Kempfer has vanished without a trace. Hired by the desperate family, Britta gets to work, and Sabrina is quickly found - unfortunately dead. Neither Britta nor the family believes it was an accident.