When a remote island nation's rainforest is threatened by the nefarious timber company, Loggocorp, the five Humans Who Know and a team of international experts develop a secret plan to stop them - and they'll need all the mice help they can get. First they must find the lost heir to the rainforest. Megan, Joey and the Mouse Nation embark on a globe-spanning mission to try and unravel a centuries-old mystery. But they're not alone. Loggocorp spies are watching their every move - while they, too, search for the rightful owner of the island's natural treasure.