Brothers, Charlie and Freddie White, along with their friends--The
Rainbow Gang--find a very unusual ancient looking chest in their dad's
garden shed. The chest magically speaks to them and sends them
underground to a world inhabited by elves. The elf world is being
disturbed by a clumsy young giant from a world below the elf world. The
ensuing, sometimes humorous, adventure brings them into contact with
lots of unusual creatures and sees The Rainbow Gang set off on a mission
to rescue the young giant, whose actions have disrupted the water tables
underground. During their adventure, the gang encounters giant
hedgehogs, giant moles and large talking fish. Charlie and his friends
come into contact with another gang--The Girls--who help them in their
adventure and both gangs strike up a lasting friendship.