(The website for the play is here)

Review will follow, this is a summary of the play.

What The Night Is For is a look at two people who met in a book club in New York City and had an extramarital affair 11 years before, but haven't seen each other since until tonight.

Roger Allam plays Adam Penzius, an architect with a summer house in Pennsylvania and an apparent desire to enter works in international competitions, while Gillian Anderson plays Melinda Metz (affectionately known to Adam as Lindy), a woman who gave up her "published" poetry for the life as the wife of the heir to the Metz Bicycles fortune and the father of his children. Roger is an award-winning actor who is almost certainly underappreciated due to his costar, and of course I expect you all know of Gillian from her 9 years as Dana Scully, a character whose love life we knew almost nothing about.

As the play opens, we find Adam and Lindy eating dinner, the food they'd ordered from room service, in Lindy's hotel room. She's in town, 200 miles from home and somewhere in the U.S. midwest, for a conference; He's here to try to sell a proposal to a potential client. It is, he says, an easy contract, one he can have his associates work on as an easy source of money to leave him free time to work on designs for competition. Over the course of the performance we find that this isn't quite the truth.

Things progress rapidly and the two end up exploring potential for a continuing relationship again in their future, and all sorts of things start to come unwrapped: Lindy had moved away without telling Adam when her husband moved to the midwest, but had she stayed for just one more week of book club he intended to leave his wife for her. Instead, when she didn't show up that night he went home, found love with his wife, and ended up getting her pregnant. She was a dancer, and went on the road the next night; He didn't hear from her for 2 months, and when she came back things weren't the same, as she was acutely aware of what she'd need to give up to have and keep the child, which she did. He claimed that if his wife could be like the woman she was the night she got pregnant, perhaps he wouldn't be in the hotel room that night.
When Lindy asked if his wife would suspect anything when he was away on trips, he surmised she wouldn't even notice, however, it was apparent that he felt guilt over the child,

Previously unbeknownst to Adam, Lindy had also contemplated leaving her husband. She had given up her poetry, published in the form of xeroxed copies, stapled and handed out in the Village, and ended up the mother of the future bicycle fortune heirs; Her guilt was in the form of the need to support her husband in his run for Senate, then ongoing, and not be caught in any questionable situations (hence her reason for having Adam in her room that night for dinner instead of dining out).

Her husband calls her more than once in the room, and finally she loses it and yells at him when he tells her he can't sleep because she's away. She notes that he can't sleep any other time either and that he always finds a way to blame her, whether it's this or his anxiety over her keeping his focus away from business.

Afterwards, she warns Adam that they "don't have much time", that her husband is only about an hour away. When he tells her he doesn't understand, she lays out for him her problems with bipolar disorder and how her husband dealt well when he discovered her problem at a dinner party she hosted, after they were already married. Her husband, she surmises, will recognize that she had an episode and come to take her home. She'd gone off her medication for the weekend before seeing Adam. Lindy tries to get Adam ready to go, but he persists, wanting something more. Neither was aware of the other's interest in something more than just wild nights of passion after the book club.

When Lindy coaxes Adam into revealing that he'd be quite content to keep company with her on the side again, she tells him that's not enough, that it needs to be all or nothing. The medication which keeps her sane also leaves her sexually dead, and it's problematic to manage going off it for a few days. He first suggests that things need not always be about sex, but she pushes that she can have plenty of mundane with her husband. She tells him she'd be taking all the risk, and him none, so he proposes what she posited as a strawman: leaving their spouses and living their lives together, him working and her writing again, finally living the life they want instead of sticking with what they have (and settled for in the first place for fear of being too undesirable to even find a better match) to avoid stepping on the toes of the people around them. Instead, they spend their time rationalizing away any chance at happiness.

She agrees, but when he tries to get her to just go now, she hedges, and proposes waiting a week. He again persists and she agrees that in 5 days, they can be together. He reluctantly takes this answer, still wanting to take her with him now, before her husband arrives. She tries to get him to leave, and the lights drop with her prodding him to leave her and give her the 5 days to prepare and him trying to bring her along with him now.