IT'S AN UNDERCOVER ADVENTURE! When a remote island's rainforest is threatened by the greedy timber company Loggocorp, the Humans Who Know that mice have evolved develop a secret plan to stop them. 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 rainforest? 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 rainforest! 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.