Psychological tension from the lagoon city on the Adriatic. A female corpse is found floating in the canal of the Grado lagoon. The case reminds Commissaria Degrassi of a series of crimes that had the coastal town on edge in the spring, but the perpetrator had confessed and is behind bars. Degrassi and her team begin to doubt his guilt. And every time the fog rolls in from the coast, it brings new horrors - is the Commissaria on the right track? Time is running out for her...