Pinky the Rat at the Brussels Sprout Museum

Two kids and their smart aleck pet rat stumble across the Brussels Sprout Museum. "It might as well be a museum about homework," they complain. They find a door marked DO NOT GO IN HERE .... They end up in a place of wildest dreams, and of mystery. How will they react How will they get back home, or do they want to Will they ever find the mysterious Mildred