ack and Annie are ready for their next fantasy adventure in the bestselling middle-grade seriesthe Magic Tree House!

ITS SINK OR SWIM

for Jack and Annie when the Magic Tree House whisks them off to the middle of the ocean. Luckily, they find a mini-submarine on a coral reef. Unluckily, they are about to meet a giant octopus and one very hungry shark. Will the dolphins save the day? Or are Jack and Annie doomed to be dinner?