As the scorching summer fades, the leaves on the branches gradually turn red. In Central Park, squirrels and raccoons discover that their winter nut supply is far from sufficient, leaving these little animals facing an unprecedented famine. Squirrels Surly (voiced by Will Arnett) and Andie (voiced by Katherine Heigl) are tasked with finding nuts. They plan to hijack a nut truck, but unexpectedly cause massive chaos, resulting in the hard-earned nuts being destroyed in a fire. After this incident, Surly is exiled, with only his rat friend Buddy (voiced by Robert Tinkler) sticking by his side. Meanwhile, Andie embarks on a journey to find nuts with her self-assured companion, Grayson. Eventually, Andie and Surly reunite in a nut shop with abundant reserves, only to discover that its mastermind is a notorious and ruthless criminal. 　　While the criminals plot a new heist, they remain unaware that a group of small animals is preparing to rob them instead...