Instead of money, Lara McClintoch's friend has bequeathed a puzzle, in the shape of an old Celtic poem. As the quick-witted Canadian antiques dealer deciphers the riddle and delves deeper into Irish lore and history, she comes closer and closer to treasure--and to secrets she shouldn't know. The lush, green hills of Ireland's County Kerry is marvelously described.  (IRE241, $7.99)