The first novel-length story from Harmony Boom Island. The Adventure of the Mysterious Adventure follows four friends on their first trip on their tugboat, trawling through the high seas in search of adventure, mystery, and adventurous mysteries. Harmony Boom Island is a giant humongous ancient creature who lives in the ocean. It is so big that its back is an entire island, complete with trees and houses and castles and stuff. It swims around the world and nobody knows where it came from or what it's doing. It has been swimming around for at least thousands of years, and probably much longer....