After a day of hot-air ballooning is ruined by a recurring quarrel, Jake and Rinah Richardson drive head-on into a fierce summer squall on Long Islands North Fork. Blinded by the flash storm, Jake inadvertently veers onto a narrow road to a small out-island, where they become stranded for the night. Already furious at him, Rinah adds this blunder to a growing list of offenses. Soon, they realize that the island is not an island at all but a living thing that is slowly taking them out to sea. Now Jake has to call on his cunning and creative resourcefulness to figure out a way to escape before the Isle of Thom takes them to a deep and watery grave.