After getting unshrunk, Andrew, Judy, and Thudd take a much needed vacation to Hawaii. While making modifications to Uncle Al's latest invention - the submarine-like Water Bug - Andrew ends up stranding himself, Judy, and Thudd underwater! Andrew Lost Under Water is the first in a four-book set that will take Andrew, Judy, and Thudd on a tour of undersea phenomena, from the Great Barrier Reef to the Mariana Trench to the inside of a whale, as they try to find their way home.