

Marina, Zig and Sharko go back to childhood remembering a famous afternoon nap by the water. Baby Marina is not sleepy and wants to fetch a mysterious object in the water while Baby Zig wants to make the mermaid her snack...
Marina dreams of sailing the sea, so Zig asks Bernie to build a cruise ship where all her friends can hop aboard! However, all awhile, Sharko believes this cruise vacation is another one of Zig's traps. When the boat is taking a dangerous course, Zig and Sharko are too busy bickering as always to save the day… who will come to the rescue?
Zig dresses up as a cute baby so that Marina takes care of him. But the mermaid is too busy and asks Sharko to babysit Zig! The shark develops strong paternal feelings towards the kid and is heartbroken when he finds out his true identity.