Nine-year-old Rico Krüger disappears without a trace. Young people soon find his body in a bag on the banks of the Elbe. The Dresden investigators Henni Sieland and Karin Gorniak are confronted with the emotional impact of such an act. Citizens are in an uproar, the media are stirring up fear, and rapid investigation results are being demanded. Commissariat chief Schnabel reacts emotionally and thin-skinned to the terrifying act and to criticism of police work - especially since he was unable to solve the disappearance of another little boy more than three years ago. Is there a connection between the cases? Schnabel publicly quarrels with data protection laws and the limited powers of investigative authorities. Sieland and Gorniak try to keep coolpreserve, but have no hot lead.
An anonymous phone call directs suspicion to Rico's swimming coach: Micha Siebert, who is a friend of the family, allegedly has a pedophile past. The detectives are able to determine the identity of the caller. Jennifer Wolf works in the school authority and lives with René Zernitz, who works as a technician at the public utility company and apparently has a penchant for children. But she doesn't tell the investigators - when the stepfather of the murdered Rico finds out about the enormous suspicion against the swimming teacher, he wants to kill Siebert. Henni Sieland is injured in the attack and has to be hospitalized. While another boy is in great danger, Henni Sieland finds the key clue in the old investigation file.