Claude has the most beautiful shell of all the crabs on the beach. It makes him feel special and he's determined never, ever to part with it. Of course, hermit crabs change their shells as they grow-in fact they often swap with each other. But when it's time to swap, Claude says 'NO!'. His decision spins the hermit crab community into chaos and it means that little Alphonso's shell is much too big. At the seaside this is dangerous. Can Claude give up his selfish ways in time to save his friend?