Ada Twist is the Queen of Questions. Like, why does hot coffee smell stronger than cold? What kind of birds live in her backyard? And, especially, why does her brother Arthur get so cranky when she borrows his stuff for experiments? But Ada’s questions really come in handy when her friend Rosie Revere needs help. Rosie’s Uncle Ned has gotten carried away in his famous helium pants, and Ada needs some answers—fast! How high can Uncle Ned float? Will he fly off into outer space? And, most important, how can they get him down? With the help of her fellow Questioneers Iggy Peck and Rosie Revere, her brother Arthur, and some new friends, Ada Twist is ready to save the day!