Summer in the Caribbean is squabble-time for Tim and his sister Mouse--whose parents are preoccupied with business--until the appearance of mysterious, ""white-haired"" Rolf and his beautiful sloop, the Windsong. He's running away, he tells them, to Mexico, where his father had wanted to take him before he died; and the threesome's search for a temporary hideout puts them in touch with black Parry, her younger brother (age eight, to the others' eleven-to-thirteen), and another inexplicable recluse, their imposing grandpa. Lessons in sailing, snorkeling, shell-collecting, and barracuda-chasing mingle with a perilous shopping trip to town and an idyllic night on ""their"" island until a hurricane exposes Granpa as the island's publicity-shy Prime Minister and persuades Rolf, alone and afraid, to turn back. Taking Rolf in, P.M. Mr. Umlatta also persuades him that his mother's dry-eyed ""be brave"" might have been said as much to herself as to him. And maybe, just maybe, Tim and Mouse will be able to remain in the Caribbean where--despite a sluggish start, some rhapsodic prose, and the rather juvenile characterizations--a good (self-testing, horizon-expanding) time was had by all.