A man wakes up in a vineyard, having lost his memory, next to the corpse of a young woman. Distraught, he takes refuge in the nearest village, but when he returns with help the body has disappeared.

Inspectors Beckmann and Brehme start to investigate the cold blooded murder of wine queen, Sophia Fink. The hero and main suspect, Johannes Fuchs, believes he can solve the mystery of his identity if only he could solve her murder. As he starts to investigate on his own, he encounters numerous inconsistencies, surprising suspects and entanglements within the village. The hero is given an unexpected alibi by the town's mayor's wife, Hanna Zepter.

During his investigations, the hero learns about an old accident: Adrian's sister, Marie Donatius, drowned in the river Ahr years ago. But is this in any way related to Sophia's death or does any villager have a more personal motive? In trying to solve the puzzle, Johannes Fuchs finds himself in danger. The police investigation reveals Sophia's secret.

Adrian Donatius, who hasn't spoken since the untimely drowning death of his sister, Marie, becomes the main murder suspect, when police finds incriminating evidence. The atmosphere in the village quickly turns against Adrian, only the amnesiac Johannes Fuchs continues to believe in Adrian's innocence.

All evidence points to Adrian Donatius having brutally slain Sophia Fink. The interrogation with the akinetically mutismic boy doesn't lead anywhere, but when it ends Adrian is admitted to a psychiatric ward. The killer is caught. One villager gets increasingly concerned having learnt about Adrian's admission.

Through the suicide of a villager, Johannes Fuchs has not only and very suddenly lost an important puzzle piece to his own identity and thus to the solution of the mysteries surrounding Sophia Fink's death, but has also come to an unravelling conclusion which in return cause more questions about a water spirit, Adrian Donatius' hospitalization, and family affairs.