Agnese, a zoologist from Caserta with a stormy character and a sharp tongue, arrives in the lagoon of Venice to study the behaviour of buffaloes in the wild. Alvise Dolfìn, a dilettante naturalist, a scuba diver and photographer in his free time, offers to take her in a boat to see barene. One day, there is a macabre discovery. Alvise is found with his chest caved in and the sand all around him trampled by buffalo hooves. The main suspect is Cesare, a handsome, peaceful male, raised and then set free in nature. Obviously, he is unaware of the turmoil around him. But Agnese knows her animals well and is certain that they attack men only in rare cases: so even if the evidence is all against Cesare, she can’t believe that the immense and docile beast is responsible for the atrocious death. There is only one person who can help her defend the reputation and the life of a number one suspect buffalo. Professor Marzio Lavetti, expert on vampire bats but, above all, a friend with whom Agnese has solved complicated cases in the past. Cases requiring defence of animals accused and put in the dock. Fortunately, the police force needs to consult the two experts because it is at a dead end, and in the midst of adventurous explorations in the lagoon and high risk experiments, the Venetian mystery will have a surprising solution in this story where the protagonists are buffaloes, followed by rhinoceroses, elephants, a Dalmatian and a Persian cat. The inventor of the ethological mystery, Danilo Mainardi, entertains us, amuses us and shows us the marvels of the animal world.