If you read your way through childhood, you’ll feel a flash of recognition when you meet Abi, the 11-year-old heroine of Hilary McKay’s utterly enchanting new novel, THE TIME OF GREEN MAGIC (McElderry Books, 240 pp., $17.99; ages 8 to 12). Abi is “hunched over her book like a diving bird on the edge of a pool, poised between worlds,” so immersed in an old copy of “The Kon-Tiki Expedition” that she can taste the Pacific’s salt spray from her perch in North London. Then something uncanny happens. Her 6-year-old stepbrother, Louis, enters the room and sees a flicker of green — a glimpse, “no more than a wing tip,” of the parrot that flew alongside the Kon-Tiki.

That moment propels an increasingly magical story, involving, like many of the best children’s books, a move to a more verdant abode, an absent mother and much-needed repair work — to a neglected house and an isolated young soul who lives to read. “The Time of Green Magic” is, in part, a book about loving books. McKay refers to Narnia and Hogwarts, and though she doesn’t mention Edwardian classics like “Five Children and It” or “The Secret Garden,” she nestles her story so snugly in the literary canon that you can imagine E. Nesbit and Frances Hodgson Burnett fluttering nearby like kindly, aging aunts.

But Burnett’s world of starched pinafores and exotic Indian servants is more than a century old. McKay sets “The Time of Green Magic” in contemporary London, busy with traffic, smartphones, working parents. Abi’s family reflects the city’s diversity. Her father, Theo, an emergency room nurse, moved from Jamaica to Britain as a child. After Abi’s mother died, Abi was raised by her adored grandmother. But Abi’s father has remarried and Granny Grace has returned to Jamaica. Suddenly Abi must adjust to life with Louis, teenage Max and their “brilliantly bossy, resourceful and kind” mother, Polly, whose work for an international charity takes her, perhaps conveniently, abroad.

Shortly before Polly flies off, this patchwork family is forced to move. There’s not much on the market they can afford, but one house — “like no other house they had ever seen” — sits empty at the bottom of a street that ends in “a dark bank of yew trees.” Ivy covers it on all sides, and by the front door is “a lantern straight out of Narnia.” Inside, the air smells “of long ago.” The stairs are “the sort you fly down in dreams.” McKay’s evocation of the house will set readers tingling with anticipation, because there is something both welcoming and eerie about the place. “Nothing wrong with a bit of eer!” says the perpetually cheerful Theo.

Fortunately, this is not some urban outpost of the Spiderwick Estate. McKay’s “green magic” unfolds more organically — from that first flicker of a parrot’s feathers to the arrival, in Louis’s bedroom, of a mysterious “cat-thing” (“golden-eyed, hot-furred, heavy-pawed”). For Louis, who hates books and is prone to tears, love for the cat-thing makes up for “the missing-ness of Polly.” Just as he could see Abi’s parrot, so, it turns out, can Abi see Louis’s cat. The two children, previously at odds, work together to figure out what to do with it as its claws, and teeth, become increasingly real. This is no Aslan — and was even Aslan really suited to domestic life?

There’s a spectrum of magic at work, not all of it emanating from Abi’s books. There’s magic in the instant when Polly and Theo fall in love, in the fact that Louis can be weeping one moment and sound asleep the next, in the way sharing secret worlds transforms warring siblings. Abi, once so quiet it was as if she “vanished,” becomes generous enough to love and brave enough to act.

Green magic has “swept through the house and bowled them over and changed their world and fixed it,” McKay writes. The real magic, of course, is all hers; and her pitch-perfect, up-to-date prose should make this book an instant classic.