TEN-YEAR-OLD Pidge has ridden his bicycle into the city of Galway, Ireland, from his home in Shancreg. While wandering through the quaint old streets he discovers a newly-opened second-hand bookshop.

Glancing through the window he encounters the bad-tempered bookseller who screams at him to move his bicycle. As he does so there is an explosion. The bookseller rushes outside and Pidge wanders into the shop. He finds himself in a dusty back room filled with junk, leftover from a previous business, a pawnshop. A shaft of sunlight filters through a murky skylight, lighting on pieces of an old manuscipt: A Book of Patrick's Writing. "Suddenly he felt that he must have them! He must have these pages!"

So begins the incredible adventures of Pidge and his 5-year-old sister Brigit. Pat O'Shea's first novel, a long fantasy for readers of almost any age, is set against a background of Irish mythology. The cast of characters includes humans, animals and insects, all endowed with powers to aid or obstruct our two adventurers on their long quest.

The dust jacket tells us O'Shea's story is set in Western Ireland where she grew up among old people who spun endless legends for the children. O'Shea has based her tale on these stories but has simplified the mythological names and language that can be difficult for younger readers. She relies on a combination of humor and adventure to propel her tale of evil come to destroy the world.

Pidge turns the pages of the book and a drawing of a serpent falls out. He grabs it before it can fall into the fire and a voice commands him to look up the chimney. He does so and sees the sky filled with glittering stars. "I write my name," says the voice and from the brightest star appears the word DAGDA (the god of the earth). Pidge, with Brigit in tow, sets out for a nearby island. Here he meets the Great Eel, known as Lord of the Waters. And the quest begins.

Enter Morrigan, the queen of evil and her two witch assistants, Melodie and Breda. O'Shea brings this devilish pair to life with a mass of colorful detail: Melodie Moonlight has blue hair, golden wheels in her ears, smokes cigars and tools around the countryside on a motorcycle pursued by faithful, shape-changing hounds. Her companion, Breda Fairfoul, has orange hair and chews tobacco.

Morrigan and her minions use these hounds to wage their campaign against the children. She knows Pidge and Brigit are seeking a pebble containing a drop of Morrigan's blood. This pebble is the source of her evil powers and she plans to take it from them if they are successful. The hounds, disguised in various ways, from rats to human hunters, pursue the two children in a tense chase, relieved by frequent comic interludes

At the beginning of the journey Pidge was given a bag of hazelnutswith instructions to break open a nut whenever things looked hopeless. He obeys and a beautiful kite bears them aloft when they are cornered by the hounds: "They sailed across the fields, low enough to notice the splashy patterns of yellow lichens on grey walls, the velvet mosses on rocks and the veining in stones. The kite lifted them up into the sky where some of the clouds lay thick as spilled cream and others danced along in gauzy wisps."

The universal theme of good versus evil with the innocence of children triumphing over all lies at the heart of this old-fashioned, delightful yarn. This is a long book but never a dull one and the chapters are just the right length for reading aloud. The Hounds of the Morrigan could be a delightful project to bring the whole family together for several weeks or even months -- providing no one cheats and reads on to the to end!