"Agnes of God," at Catholic University's Hartke Theatre through Sunday, is that rarity: a student production that can not only be measured by professional standards, but comes away with colors flying.

This rendition of the Broadway drama by CU graduate John Pielmeier is as potent as the touring version that played the Kennedy Center a season ago. And in one significant respect, it is even better. It focuses squarely and soberly on the mystery of Agnes, an oddly ethereal nun, who has given birth to a child she may have strangled.

To the extent that it hyped the lurid theatricality of an admittedly bizarre case, the touring production had a touch of the National Enquirer about it. Much of the hyping was traceable to Elizabeth Ashley as the court-appointed psychiatrist charged with determining whether Agnes was blessed by God or merely suffering the fallout from an abused childhood. It was a Star Performance, seemingly as concerned with grabbing the spotlight as with rooting out dramatic truths, and some of its excesses spread, as if by contagion, to the other members of the cast.

The three actresses director William Graham has assembled for CU's production are involved in no such games. Their technique may not yet be fully seasoned, but they conserve it for the business at hand. There is no useless embroidery here, no emotional grandstanding -- just an honest, direct exploration of the play.

Joanne Schmoll makes a splendidly affecting Agnes -- suggesting, as she does, the child in the adult, the dementia in inspiration and the profanity in purity. She has just a hint of metal in her limpid voice and her eyes are both luminous and luminously troubled. It's a wide-open performance that, paradoxically, preserves all the tantalizing ambiguity of Agnes.

Kathleen Shea, as the crusty mother superior who is fighting to protect Agnes from the probings of modern psychiatry, contributes a sharp, down-to-earth portrayal. And Deirdre Donohue, as the chain-smoking shrink, conducts the investigation with slowly diminishing confidence as the disturbing implications of Agnes' life begin to unsettle her own soul. When Donohue is required to address the audience directly, she tends to take on the overexplanatory airs of a kindergarten teacher. But in her scenes with the other two, she is persuasive.

The abstract scenery and lighting by Robert C. Torri are first-rate, and Graham's direction firmly addresses, but never belabors, the spiritual issues of the play. You might expect Catholic University to bring a certain empathy to the plight of "Agnes of God," but a student production with this much assurance qualifies as a genuine surprise.