Park Woods and Whylder Wood have long been safe havens for the creatures living there. But peace has bred complacency, and now a dark threat festers deep in the woodland, spreading a poison that infects both bodies and minds—starting with a colony of rats.

When Cory, a well-loved hedgehog, discovers the poisoned stream and the bodies of affected animals, he feels compelled to act. Despite his doubts, Cory rallies a reluctant group of apathetic, meek, and traumatised creatures to confront this growing menace.

Against overwhelming odds, can Cory's unlikely army march to defend their home?