This is an accomplished and, at times, harrowing novel full of the kind of psychological power and exactitude that first-rate fiction does so well. I found myself wincing half the time, whispering, wishing, willing the characters to take other courses.

For those unfamiliar with Richard Bausch, he has long been celebrated in America as a practised purveyor of Chekhovian precision. Before, During, After is his 12th novel and it again gives primacy to the observation of character. For Bausch, it is in the moment-to-moment detail of life that devilry and virtue vie for the human soul. This time, though, he has also written an explicitly widescreen book, since the action takes place against the backdrop of 9/11 and the inner lives of his two protagonists are detonated on the same day that the twin towers fall. Thus the title, and thus does Bausch seek to have the private refract the public.

Natasha Barrett is 32. Ostensibly, she is committed to her work for a senator in Washington, but she has entered a period of lassitude following a heartfelt affair with a married photographer. Michael Faulk is 48, three years out of a failed marriage and only just out of the Anglican priesthood. Ostensibly, he is warm and well adjusted, but inside he is having a crisis of faith and self-belief. These two people find each other and love does all the things that love can do – rescues them, remakes them, rekindles their desires. They decide to marry. But before this, Natasha must honour a holiday commitment to go to Jamaica with Constance, a wealthy friend. And it is on this holiday – “during” – while trapped in a luxury hotel and uncertain if her fiance in New York is still alive, that Natasha is raped on the beach.

Two-thirds of the book concerns itself with “after”, and here Bausch’s subtle art is everywhere on display. Or, rather, not on display, because Bausch is an expert at invisibly managing intensity and human complexity. Natasha is unable to talk about what has happened to anyone. She perseveres with the wedding, although her “deepest self” is “fractured”. Part of her hell is that Constance witnessed her, drunk and stoned on the beach, “leaning over [her attacker], kissing him. Deep.” Yes, says Natasha, “I – I kissed him. I kissed him. I felt sorry for him. But that was the end of it.” But this tragically mistaken reading of what happened will transform in Faulk’s imagination into a mushroom cloud of suspicion, jealousy and rage. And eventually, the once-priestly Faulk falls into a fury and smashes through a locked bathroom door to demand of his wife what she is hiding. It is an act of masculine violence that the reader is all too aware could not be worse for Natasha as she cowers, terrified, behind the shower curtain. What world can they live in after such trauma?

Bausch also dedicates fine writerly attention to his minor characters; the novel is thronged with walk-ons who come instantly to life and furnish half a dozen excruciating side-scenes that echo and recapitulate the turbulent themes of the main narrative. Those themes are most obviously to do with trauma, but also with theology. The attacker is oddly formal in his speech and his name, Nicholas Duego, is deliberately suggestive of the devil. Faulk and his aggressively atheist father argue drunkenly about barbecues, fidelity and whether God is merciful or wrathful in what is one of the best painful father-and-son scenes I’ve ever read – “Thought I’d tell you a few things, son … Get to know you better.” Madly, Faulk writes down his foolish doubts about Natasha in a private journal in a prose style that apes the cool argumentative phrasing of Aquinas’s Summa Theologica – “Reply Objection 2: There must be some demarcation between love as possession and love as it was …”

But beneath all this, Before, During, After is about psychological isolation. Even “before”, Natasha finds it a “disconcerting revelation – how rarely she had been herself with any of the men she had known”. And “after”, Faulk struggles “each moment to forget his suspicions while at the same time seeking to have them answered once and for all”. This precisely piloted psychology is Bausch’s greatest proficiency. When Faulk arrives at Penn Station, trying to leave New York a few hours after the attacks, there are two sentences that might well stand as a summary of Bausch’s vision for the whole novel: “A great roar of voices reverberated in the high vault of the ceiling and yet no one appeared to be speaking to anyone. Everyone looked isolated and bewildered.”

• Edward Docx’s The Devil’s Garden is published by Picador. To buy Before, During, After for £11.99 (RRP £14.99) go to bookshop.theguardian.com or call 0330 333 6846.