Pidge, 10, unwittingly unleashes an ancient, evil serpent named Olc-Glas in modern Ireland. He and feisty little sister Brigit, aided by the Good Dagda, then strive with the Evil Morrigan to recover an ancient talisman that can be used to control Olc-Glas. Pidge finds Olc-Glas ensnared in an ancient book. Two comic-opera witches arrive on a motorcycle, followed by their dreadful hounds. The hags and hounds attempt to recover Olc-Glas; when joined by the third, most evil hag, the chase becomes earnest. Pidge, however, has been contacted by Dagda and given magic gifts; he and Brigit imprison Olc-Glas and set off to find a drop of the ancient Morrigan's blood. Aided by an astonishing array of creatures--bumbling frogs, heroic earwigs, argyle-knitting spiders, a prolix weather vane, and more--they escape, rescue the blood drop, and defeat the evil hordes. This long story is full of charm and invention, but it vacillates between slapstick and adventure. The children are impossibly precocious and the magical rescues begin to get boring, but the story keeps moving. Some readers will bog down, but those with an interest in words and myth will be captivated.