In this final story of Warren's thrilling adventures, the young manager is adjusting to the demands of running a floating hotel and is planning his thirteenth birthday party. But then disaster strikes! The Warren Hotel is shipwrecked on a strange island, and Sketchy is kidnapped!

Warren and his crew of friends set off on a daring rescue mission across the high seas, where they meet a delightful new cast of characters that includes wizened pirates, a sea witch, and a talking clam. As Warren pursues his many-tentacled friend's kidnappers, he will learn the truth of Sketchy's mysterious origins--as well as one final secret of his beloved Warren Hotel.

Once again, readers can expect mesmerizing illustrations on every page, along with plenty of riddles, puzzles, and adventure galore!