The fourth and final play of the Theater at Monmouth season is a strange mixture of heart-rending monologue, adolescent hormones and wisecracks, and anachronism. Weaknesses and faults and cracks are everywhere, and the first failure may have been in choosing this play at all.

“Shadowlands” by William Nicholson is the story of the relationship between the very English writer C.S. Lewis, most noted for “The Chronicles of Narnia,” “The Four Loves” and “A Grief Observed,” and the very American woman of seemingly no redeeming grace — aside from shaking an old man out of his lethargy.

Supposedly the story of a great love between an aging (58) Oxford don and the younger but not young (41) divorced mother who sweeps him off his oh-so-staid feet, there is just one problem with it: Never for a moment do I understand what he sees in this woman who so mesmerizes him. Often, in life, we do not understand what makes a relationship work, but this is theater. There should be something there for the audience to hold onto. Here is a great thinker falling for a woman with the tired looks and caustic edge of a waitress from a barbecue house on the other side of the tracks. Is she sharp? Yes. Is she funny? Yes. Do you marry her? Not in this life.

Nicholson has done a disservice. He has been less than honest. Lewis is surrounded by pretty, tweedy, ivory-tower types who dislike his love, so you dislike them. Would you have thought differently of his drinking friends if you had known they were actually people like J.R.R. Tolkien and Charles Williams? Here is a man speaking authoritatively on love. What would the audience think to know this man entered marriage when he was approaching 60 as a virgin? This is not a play about a fictional character. This is a play about a historical personage.

The production is flawed from the program forward. The director’s note in the program opens with the line, “This is one of those plays.” That is as much sense as you will ever make of this relationship.

Nevertheless, Michael O’Brien as C.S. Lewis is brilliant, nothing less. Lewis was so charismatic people flocked to his lectures. O’Brien gives lectures in the play about God, divine love, suffering, desire and how suffering rouses a deaf world from its selfishness, lectures that are riveting. O’Brien could make the yellow pages believable. Unfortunately, his periodic one-man shows are interrupted by the natterings of the other characters. I believe him when he says he loves this woman. I simply don’t know why, and all this lecturing on love is not the same as reciprocity in an adult relationship.

Joy Gresham, the love of this stilted, stuffy old man, is played by Chloe Leamon. Joy was disliked by Tolkien, Williams and all Lewis’ friends in the play as she should be. This is not some fascinating exotic. This is the pushy, abrasive lower-East-Side type capable of making a bad impression anywhere. If the play had portrayed her as the abused, beaten, mistreated wife she was, we might have had more respect for her. As is, she is just another woman unhappy in her marriage to a man who has found love elsewhere. If we saw a woman of the times (’40s, early ’50s) we might be more impressed, but there is no period hair style, no real sense of the time she lived in emanating from the character.

James Bodge is wonderful as the curmudgeon with nothing nice to say about Joy even after her death. His “Riley” is a wonderful touch in a play often too heavy on the pathos.

Devon Louise Jencks and Andrew Shulman as bumbling government clerks again turn moments into magic. Jencks in period hairstyle gives us an understanding of what we should expect to see at center stage.

Joan Jubett does a fine quick turn as the nurse, as does David Harbour as a waiter.

Charles Weinstein is an unmined resource as “Warnie,” Lewis’ brother and roommate of the last 20 years. In reality, he was the only person with a real respect and caring for Joy among the friends. Weinstein seems stifled here. This part could give great relief from the unremitting angst of the love-found-and-lost-to-cancer-scenario we have all become too familiar with from made-for-television movies.

Nicholas Rioux as Douglas is completely believable as the quiet, obedient and loving son.

The costume designs of Lucia Williams-Young are a disappointment. Into this world of gray and tweed and dusty books and people comes an American much expected to contrast with everything they know and understand. Instead of some breath of visual air, Leamon enters looking more like someone seeking the position of nanny or housekeeper. Nothing here sets her apart in this suit that puckers and pulls but does effectively convince us she bought it off the rack at a sale on the East Side. In the second act, Williams-Young has costumed Leamon in such a way that the character is lifted out of and above the others, making the character of Joy more accessible.

The accents of the men are weak. They should all be speaking like Prince Charles. Then there would be no need for Leamon to emphasize the contrast between English and American voices by making her lines sound so low class.

Lines were confused and repeated. And Americans put milk in their tea, not tea in their milk. Some actors are wearing makeup and others none.

Lewis had a major crisis in his philosophical life coming to the decision to marry a divorced woman of Jewish heritage. This has been reduced to sophistry, the clever thinking of the oh-so-clever.

Bob Colona has directed a play that has many flaws that are not written into the script. The play succeeds because of the strength of the script and in spite of the direction.

Did this play move me? Yes, but the telephone company has commercials that regularly make me think of things in my own life that were missed or are missing. Neither can be called great theater.

“Shadowlands” is running in repertory through Aug. 30 with “A Midsummer Night’s Dream,” “The Miser,” “Hamlet” and “Aladdin.” For tickets and information, call 933-9999.