For fisherwoman Victoria Ludolf (Magdalena Kronschläger), it seems like a scene from a horror movie when a decaying boat drifts towards her in the middle of Lake Constance. On board is the tied up and already skeletonized body of 16-year-old Roman Steingass (Valentin Hagg), who disappeared without a trace 15 years ago. Roman was the main suspect and Oberländer the lead investigator at the time of the murder of teenage Anouk Bergdorf. Oberländer is now once again confronted by the traumatized families of Anouk and Roman. When fisherwoman Ludolf is also found murdered a day later with a piece of rope from the ghost ship in her hand, the case takes a dramatic turn, because now all those involved in the old murder case have become suspects.