Under mysterious circumstances, the restorer Lukas Albrecht drowns in the Canale dei Marani in Venice. While the easy-going Commissario Santo sees no criminal offense, the victim's widow resents the details. Anna, who is traveling from Vienna with her eleven-year-old son, doesn't believe it was an accident: her husband didn't have any alcohol in his blood, he knew the lagoon and could swim
The manufacturer Xaver Frey is forced into bankruptcy by his bank and decides to commit suicide in a sleeping car from Vienna to Venice. There he encounters the sleeping car attendant Horak, who is about to retire and who uses every legal and illegal means to prevent his suicide.
