The mystery of spirits loosed, of souls possessed, assumes a dimension beyond fantasy in Alan Garner's latest book, which is his finest if also his most elliptical. In an old house in a Welsh valley three adolescents discover, in a sealed attic that has been emitting inexplicable sounds, a dinner service decorated with flowers in the form of an owl; and the trap one sets disgorges an owl's pellel, not a whole mouse. Gwyn, son of Nancy the housekeeper, is momentarily mesmerized by the plates but it is Alison, come to stay with her new stepfather and stepbrother Roger, who is obsessed with the owls. From a copy of the mythical Mabinogion and the cryptic remarks of handyman Huw Halfbacon, reinforced by the instinctive sympathy between them. Alison and Gwyn realize that they are, with Roger, reenacting an ancient tragedy of jealousy and retribution that has recurred in each generation. The tensions among them are very real, very much a matter of class; Gwyn is the clever comer, Alison is the aristocrat. Roger is the snob In scenes which approach the intensity of Strindberg, Gwyn forces Alison to face him, and herself, recoils when he thinks he's been betrayed, ultimately humbles Roger and gives him the clue to saving Alison. However gripping, this is not lugubrious and not without humer, albeit ironic. An uncommon book for uncommon readers of some maturity.