Beware, lest in scouring off the rust, you break the vessel itself,"" the abbess had said, and the central focus of this handsome and moving first novel by the daughter of Sean O'Faolain is the tragic and futile pursuit of a reality beyond humanness--by which the seeker is destroyed. The founder of a 6th-century convent in Poitiers is the Thuringian princess, Radegunda, captive wife of a conquering king. A passionate woman who rolls naked in the snow to overcome the hateful pleasures of a sex-sated body, Radegunda believes she has given up the world for God and becomes intoxicated with the thrust of her own salvation. Her protegee Agnes is wary of spiritual excess, yet as the first abbess, she does not face the consequences of her own self-indulgence. Agnes conceals a liaison that results in the birth of a daughter, Ingunda. When Ingunda, as a young nun, discovers her mother's sin, she does penance as an anchoress, bricked off in her cell, and racked by nightmares. Ingunda is killed in a marauder's raid brought about by convent dissensions, and grieving Agnes takes her daughter's place in the cell. The idyllic community, like other utopias built on the negation of the totality of human life, is doomed to fatal incursions and decay. With dialogue of vigorous content and wit, full-bodied characters and timeless inferences--an impressive initial effort.