It isn't much of a secret except that brand new step-brother Robert won't talk about it; he's planning to attempt a salvage of a cabin cruiser against his father's orders on the rented boat, The Sea Witch. ""Sea Witch"" is also the name of a snack bar and of its mysterious young owner, who gives Jennifer (thirteen) the clue of how to win Robert over. The only action comes at the end when Jennifer, trying to help with the salvage and thus gain Robert's friendship, almost drowns and is rescued by stepfather Angus MacCloud and Robert. Jennifer and younger sister Pam's mother is an interior decorator, not a good housekeeper, and thereby hangs considerable hilarity as she looks her way through her new Scottish cookbook, only to gratefully embrace the return of practical, brisk-tongued housekeeper Trappy at the same moment that the pressure cooker explodes its load of huggis on the ceiling. Despite the comedy and Pam's effervescence, the commonplace plot--petty mystery, second marriage and reluctant offspring--snatches up a contrived ending and falls flat.