On a volcanic island that has recently opened to the public, the gang finds a talking shell that encourages them to indulge in their fantasies. Then, when the volcano starts to erupt, they must escape not only the island but the power of the shell.

The gang emerge from a cave to find themselves in an alternate reality… where Uncle Charlie never went missing! But it soon becomes clear that their presence is affecting the island and in order to save it, they must return to their own reality.