Life in “Rapidity over the Fjord” goes on as usual. The guests of the boarding house, the dog Samson and the cat Roberto, are enjoying peace and quiet, when suddenly the keeper comes from the lighthouse and reports in horror: a terrible yellow eye has appeared in the sea! Trying to find out what it is, Samson, Roberto and their friends find themselves on a submarine owned by a bloodthirsty wolf - Captain Nero. Friends will have to escape from captivity and defeat the treacherous wolf, and also meet other inhabitants of the underwater world - the Snapping Shark, a mechanical beaver and apathetic snails.