Plummy finds some nice shells on the seaside, especially one that lets him listen to the sound of the sea and even one with a nice, big pearl inside! Plif and Plops want to have such nice things too, but all they can find are some itchy algae and pebbles. So they morph themselves into a crab and a pelican to get their „hands" on these collection. Plummy finds out who played a trick on him and is plotting his revenge: he turns into a tiny, little starfish and let himself be caught by Plif and Plops. But once he is in their hands he turns into a giant octopus and gives them one hell of a scare. In the end all three of them are sitting in a sand castle decorated with Plummy´s shells.