Kerstin Wilm, the private cleaning lady of Precinct Chief Girwidz, is supposed to spruce up the police station for a press event. But just as she's about to clean up the mess left by Hubert and Staller, she dies of poisoning—from a tea bag! The first clue leads the two police officers to a luxurious breakfast café. According to a reservation confirmation, the dead cleaning lady had arranged to meet an unknown man there for breakfast. Surprisingly, the unknown man turns out to be Precinct Chief Girwidz. The cleaning lady had asked him for a favor in exchange for cleaning the station. Girwidz can't say what that favor was.