When two investment bankers are found dead in Frankfurt - each with an arrow in their chest - Markowsky, the head of the homicide division, suspects a serial killer is on the loose. Commissioner Andreas Rauscher interrupts his vacation, even though all his attention is focused on the impending birth of his first child. As the head of the special task force "Robin," Rauscher takes charge of the case and uncovers mysterious monetary gifts, murder calls in a fan blog, and foreign feathers during the investigation. As the due date approaches, the "Robin" case takes an unexpected turn and culminates in a spectacular showdown.