Grumbling mountains and winged mules? The biggest little giant's next adventure is riDONKEYulous! Muncle Trogg, the smallest but smartest giant around, is worried. Mount Grumble is beginning to burp and belch! Muncle can't help recalling what his Smalling friend Emily said about it really being a volcano. (Uh-oh.) Meanwhile, all the other giants are partying while home burns because the Smallings have fled their town farther down the mountain. It's a good thing clever Emily has a plan so crazy, it just might work. Muncle "mules" it over: The giants won't heed his warnings, but would they listen to the wisest, most wondrous animal of all? Maybe -- when donkeys fly!