When a remote island's rain forest is threatened by the greedy timber com pany Loggocorp, the Humans Who Know (that mice have evolved) develop a secret plan to save the forest. And they need all the help they can get from the Big Cheese, Trey, and their other friends in the Mouse Nation.

First, the team must unravel a centuries-old mystery: Who actually owns the rain forest? The mission to find that person brings Megan and her family across the ocean to England, where everything starts to go just a little bit . . . weird. Loggocorp spies are watching the family's every move as they, too, search for the rightful owner of the island's natural treasure.

It's a race against the clock to save the rain forest The trail leads to a duke's palace full of strange guests and a clan of helpful British mice. And Megan, the most famous human in the world (among mice), has to face her biggest challenge yet.