Two pest controllers are called to an eco-café in a country park to investigate what begins as a routine vermin problem - but as nightfall approaches an avalanche of deranged squirrels descend, wreaking revenge and mayhem on the staff and visitors in the park. With many fatalities the survivors take shelter in the café as a freak storm takes out the power and communications leaving them isolated and under attack. An eclectic mix of survivors include pest controllers, a sulky teenager, hypocritical vegans, and a drug dealer - there is only an outside chance of survival...