When Willi s father is abducted and is only released for a valuable statue from his art collection, Tim is the only one who believes Willi that the police are on the wrong track. Together with the smart policeman s daughter Gaby and the highly intelligent outsider Karl, they start to investigate on their own. Against all odds the four discover a conspiracy. In the course of their first big detective adventure they grow together into a committed community, and so Tim, Klöschen, Karl and Gaby become the band TKKG.