"Shadowlands" has the difficult task of selling us a love story in which half of the happy couple is — to great extent — unlovable.

The play by William Nicholson centers on C.S. Lewis, author of children's favorite "The Chronicles of Narnia," and American poet Joy Gresham. But the play is about people, not authors, and these two people are indeed an odd match.

Lewis is an Oxford don and a confirmed old bachelor living contentedly with his elder brother. Both are members of a starchy Old Boys club that meets periodically to drink port and indulge in arcane debates over subjects that include women and fornication — both of which they find to be distinctly overrated.

Gresham, mother to a young son, is in a troubled marriage. She begins a long-distance correspondence with Lewis that is best described as a highly literate pen- pal crush. She visits Britain and wrangles a meeting. Intrigued and flattered, Lewis agrees. He discovers they are soulmates.

The Old Boys cluck their disapproval. She's a woman, American and pushy.

But what elevates this unlikely pairing is Lewis' search to validate God's love — a subject on which he directly addresses the audience three times during the play — attempting to answer the hoary question, "How can a loving God allow his children to suffer?"

The two themes connect when Gresham develops bone cancer. Lewis has entered into a pro-forma civil marriage with her for the sole purpose of allowing her to remain in Britain. But her physical suffering awakens in him a deeper love that he formalizes with a second, religious marriage ceremony.

Directed by Melinda Maltby in The Actors' Group's tiny Yellow Brick Studio, the play works largely because of James Aina's performance as Lewis. Aina's characterization is both remarkably articulate and deeply felt.

Coming to Christianity as an adult, Lewis embraced his faith as an academic and a theoretician. It was not until his wife's suffering sharpened his understanding that he could experience faith on a more visceral level. "Why love if losing hurts so much? I have no answers anymore. The pain now is part of the happiness."

Aina's performance makes these words live on a human level and, to a large degree, we accept his statement of love for Joy Gresham, even though we — like the other characters in the play — cannot validate that love from what we see.

As Joy Gresham, Hannah Schauer Galli is both direct and reserved. The character says what she wants, then cuts her visits short. Even in the hospital with a diagnosis of death, she asks permission to speak frankly. She sorts out Lewis' clothes closet with the same take-charge directness that she uses to point out his blind spots.

They are intellectual equals, and Lewis says he loves her. In the world of the play, we must accept that at face value even though we can't share it. We hear the words and resonate with Aina's delivery like tuning forks on the same frequency.

Sam Polson does well as the accommodating elder brother, and David Alpert is fine as an academic prig with an incurable insensitivity to others. Jimmy Davis and Mickey Graue alternate in the role of Gresham's young son.

Logistically, the numerous set changes become an annoying delay — especially when the scenes are short. However, limitations stimulate creativity, and Andrew Alvarado's creative use of a fireplace chimney as a fold-down Murphy hospital bed merits applause.

Joseph T. Rozmiarek has been reviewing theater performances in Hawai'i since 1973.