Hampstead Heath is under attack! A developer plots to build houses on London's best-loved open space. Only Hamster and his friend Vole are in the know. So can they save their homes and the Heath from this fiendish scheme? With the help of the wily crows and a regiment of moles, not to mention the assistance of a passing squirrel, Hamster and Vole fight back. But their vigilance drops, and the bulldozers are advancing across the precious land, digging gaping holes in the Heath. Is all lost? Will Hampstead be blotted out by the greed of the developer?