Coming from New Zealand with a detour through England, a wickedly funny, laugh-out-loud first novel from Reidy (stories: Modettes, not reviewed) about two young sisters struggling against the strictures of Catholicism. Nothing ever happened in Chatterton, New Zealand, in the late 1960s--at least so Theresa and Catherine Flynn believed before they spotted the Virgin Mary hovering above their backyard lemon tree. Weary veterans of endless rounds of the game ``Martyrs and Suffering Virgins,'' in which players eagerly reenact the whipping and torturing of their favorite female saints, the prepubescent sisters still find themselves unprepared for the sight of the Virgin herself. All Mary wants them to do, it turns out, is deliver a sealed, handwritten message to the Pope. Awestruck, the two obediently pass the Virgin's letter on to their mother--who promptly turns it over to her sternly devout husband--who self- righteously opens and reads it before passing it on to the local priest. Disagreeing with the letter's content (the Virgin wants the Pope to acknowledge the importance of contraception), Terrence Flynn alters the message to conform with his own and the Church's misogynistic doctrines. The result, as this wacky family history would have it, is Pope Paul VI's Humanae Vitae forbidding the use of the Pill--an edict that forces Mary to reappear on Earth (with the girls as her witness) to initiate a movement intent on helping women control their own procreative destinies. Meanwhile, Theresa and Catherine go about their own very mortal lives--experimenting with sex, falling in love with a long-haired cousin, a doctor's son, a best girlfriend, and whatever other target wanders into their paths--while struggling to ``be good,'' whatever that means, in the face of their father's violent temper, their mother's depression, the local monsignor's failure to guide them, and the utter chaos of life in a houseful of Flynns. An offbeat, surprisingly entertaining look at Catholic girlhood, by a writer with a predator's eye for comic detail.