Managing Director Stefan Markowski was killed on the grounds of the "Atlantis" amusement park. Criminalists Ehrlicher and Kain discover strange digs near the roller coaster. In addition, threatening letters indicate that there are blackmail attempts in the popular park. When the inspectors are on the trail of the alleged blackmailer, Peter Radke, who has just been released from prison, he is found dead in a parking lot at the nearby bathing lake. In his trailera self-made map is hidden on which the coordinates of the amusement park, a new housing estate and an abandoned opencast mine are listed. Are the hiding places of the millions he had put aside marked on it and did he want to dig them out now? The detectives find out that Radke is behind some extortions - and the amusement park was not the only victim of extortion. Apparently, some people made some money from Radke's dirty dealings.