After years of being a foster child, 13-year-old Chad isn't about to settle in comfortably for the summer with the eager Sorenics: the last thing he wants is to be beholden to anyone; the first, to be reunited with his mother--whose recent letter, saying she's to be married (and implying that she's giving him up for adoption), he doggedly refuses to absorb. Rejecting both phys-ed teacher Mr. Sorenic's sports enthusiasms and nurse Para Sorenic's low-key sympathy, he fastens on a stray cat--a wary survivor who does respond to Chad's overtures. But though the story is a set-up, it doesn't work out quite the way you might think. All the while that Chad is giving ground--making friends with thoughtful 14-year-old Polly, bridging his differences with pushy twelve-year-old Bob, deciding ""they were all decent"" people--he's trying to save the cat from being wiped out by hostiles. And when he's reconciled himself to the loss of his mother and come to welcome (rather touchingly) the Sorenics' desire to adopt him, he's still faced with the problem of the cat--which seems to want to be on its own, whatever the dangers. Concluding (rather too literally) that ""A cat didn't need a family the way a kid did,"" Chad makes the decision--to the Sorenics' surprise--to leave it behind. Though a practiced reader will spot the signposts along the way, Chad's shift from suspicious hostility to self-conscious involvement to a deliberate, joyful ""Hi, Sis"" (via the appropriate trepidations about ""just moving into a family"") is convincingly and warmingly carried off.