Twins Sally and Emily Berg and their cousins (of The Christmas Revolution, 1987) vacation on the Jersey shore with their extended family--including fifth-wheel Miranda, a cousin from Colorado whom their parents expect them to befriend. The Bergs and their two contemporaries, Jake and Jenny, call themselves the ""Four Seasons"" and play a secret game in which they are orphans seeking their real parents. They remember Miranda, with some truth, as a whiner, a tattletale, and (on one occasion) a lair, and try to avoid her; but Sally's natural kindness leads her to the discovery that she and Miranda have things iii common, which in turn leads inevitably (with the help of their sensible, nonintrusive parents) to friendship all around. Though pleasant and competently written, this is a little tame: a flamboyant, grandmotherly artist who befriends the girls; money-earning projects for a trip to Atlantic City; and the discovery that overprotected, adopted Miranda broods about her ""real"" parents--thus sharing the others' universal fantasy--are standard stuff. Still, a wholesome, realistic ""chapter book"" about kids who happen to be Jewish.