When Mole takes a break from his cleaning and wanders down to the river bank, he meets the Water Rat, and a friendship is instantly formed. The two, together with Badger, spend a glorious summer messing about on the river, picnicking on the bank, and taking life easy. But when their hapless friend Toad gets into a spot of bother they dash to his aid. Soon the four friends are fighting to save Toad Hall from the dastardly stoats and weasels.