A series of burglaries in Norden is unsettling the entire town: valuable china is stolen from the tea museum, and at Emma and Lukas' neighbor Kunschewski's house, a East Frisian tea set is also taken. He suspects the Nordseedetektive, as the children were filmed by the surveillance camera on his property. However, they were only trying to retrieve their ball! The young detectives begin their investigation to dispel the false suspicion.