Fly-tippers cause havoc when they dump toxic waste on an unsupervised land-fill next to the old farm. Creatures start dropping like flies as the poison spreads. Animal meetings are held and the word goes out; Fly, walk, waddle, but take the next bus out.

Myrtle Mouse and her surviving kid brother, Wilbur, are one of the last to leave their home. Joined by Thomas Rat and Maurice Mole they attempt the long and hazardous journey to a distant quarry encountering numerous adventures along the way and, thanks to the conniving, scheming, sharp-as-a-button Walter Worm, the remnants of the group finally reach a place of haven.