Jon Doyle’s debut novel tells the story of Mack O’Brien, a young man who went to a seminary to study for the priesthood but was asked to leave because he had no real calling, and has therefore returned to his family home in Wales to work out what to do with his life. Cheek by jowl with his ailing, deeply religious mother, and a father struggling to process the grief of his own parents’ recent deaths, he finds himself drawn into participating in a local theatre production – playing a disciple in Owen Sheers’s now-legendary Passion of Port Talbot, an immersive community-led re-enactment of the crucifixion that took place over several days in Port Talbot in 2012, starring Michael Sheen.

Mack is recruited after a steelworker from the plant where he works as a security guard drops out of the show. Material enough for a novel already, one might think, but all this becomes more or less background noise when, on the same night he agrees to be in the play, Mack bumps into Siwan, a young woman he was close to at school. Siwan’s mother was an environmental activist who ended up going to prison for her protests. Siwan had visited him at the seminary on the day he agreed to leave the priesthood and said to him, “forgive me father, for I am about to sin”. The nature of the sin she is intent on committing becomes the focus of the novel.

They weren’t exactly a couple, Siwan and Mack – never slept together, never kissed, never even really talked in school. What they did share was nights in the Plaza cinema, where they’d sit together in the dark to watch movies, and Siwan would let her leg rest against Mack’s. This was their only point of connection, and from the way he interacts with his parents in the present, one suspects it may have been practically the only point of real human connection Mack has ever had – he certainly can’t talk to his father, and he can only talk to his mother about God, the local priest and the TV. How heartbreaking, then, that Siwan’s present interest in Mack seems to be connected to his job as a security guard at the Port Talbot steelworks, which we quickly realise she’s planning to blow up during the weekend of the play. The works will be shut for a strike to draw attention to proposed lay-offs; Siwan’s plan is to take advantage of them being empty and set a bomb off without killing anyone. But of course, to do that, she needs to get a bomb on site. Lucky for her that a boy who yearned for her in school can make that possible.

There is so much in this book that is rich and involving and emotionally charged. It’s more than can remain in focus the whole way through, and some elements of the work ebb as the narrative unfolds. Mack’s mother’s illness and the death of his grandparents remain harrowing but largely off-stage sorrows; the strike, once determined, is never revisited. The play stops mattering; Mack misses the crucifixion, calling it “silly”, and by the time he bumps into a Roman centurion lying on a sand dune, having dressed in his own priest’s vestments for the occasion of the bombing, that plotline has come to feel like a McGuffin, or perhaps more accurately a simple allegory of the real heart of the matter. The novel eventually becomes something much more focused and intense – it’s the story of a man who made a wrong start in life, revisiting the boarded-up site of his youth and haunting it, unable to enter back in. He is confronted by colossal loneliness and manipulated by the one person who seemed to offer a route out of his solitude. Eventually, it becomes a novel about nihilism – seeing no exit from a dead-end future, Mack decides to help someone blow the whole place up, simply because he at least cared about her once. It’s a devastating via dolorosa.