In this fast-paced, entertaining first novel, Ava learns that friendship rises above differing opinions, upbringings, and parents. Ava is thrilled when exciting Zinny moves to town--she's no longer the only new gift. The two bond instantly, but soon discover key differences: Ava keeps a veritable zoo of pets including a rabbit, a rat, a dog, and a lizard, while Zinny is not an animal person. When the rabbit eats Mrs. Weston's petunias, Ava's father, a veterinarian, and Zinny's father, animal-indifferent, exchange words, but the girls' friendship transcends the tiff. When a second misunderstanding--Mrs. Weston drowns a raccoon--tears the girls temporarily apart, their budding maturity enables them to resolve their differences, and makes their friendship stronger. Koss's charming, multilayered story blends childlike issues and feelings with larger questions about animal cruelty; she knows where to draw the line, without forcing judgment. On-target characterizations and the sentiment that friends don't have to be clones put this a cut above most friendship fare.