Kassandra Voss has just opened her guesthouse in Wustrow on Fischland when she finds a guest fully dressed, but wet, dirty, and above all, dead on his bed. The man was drowned in the Bodden. When it turns out that he was not who he claimed to be, Kassandra herself comes under the police's scrutiny. Unexpectedly, she receives help from her neighbor Jonas and Fischland expert Paul, with whom she soon begins to investigate on her own. But then, one of the main suspects checks into her guesthouse.