Sophie Mouse and her friends are playing hide-and-seek near Butterfly Brook. Sophie finds the perfect hiding spot, but she finds something else, too! It's a glowing cave. The problem is, when Sophie tells her friends about her discovery, they don't believe her! After all, who's ever heard of a cave that glows? Now Sophie is on a mission to prove she's telling the truth!

A mysterious compass with a fifth direction transports a young boy to an extensive cave system filled with bats, treacherous drops and hidden dangers. Luckily, survival expert Bear Grylls is on hand to guide him safely out, facing his fears and gaining in confidence along the way.