André the shark has invited Irina the whale out on a date but she has really bad breath and prefers to hide rather than own up to it. Roger and Fatou decide they really have to help the whale by teaching her how to brush her teeth. The thing is, her problem goes well beyond a simple question of bad hygiene. Our heroes decide to go take a stroll deep inside Irina and there, in her belly, they meet Michel, a castaway who is a bit of a nutcase and who has set up his restaurant inside the whale! But the bigger problem is that he is quite happy where he is and has no intention of leaving…