Tom Kettle has seen enough evil in his life. The 66-year-old Irishman has retired from his career as a police detective and moved to a small lean-to adjoining a castle in the town of Dalkey. He's relieved to be done with his days in the Garda Síochána, Ireland's national police service: "All his working life he had dealt with villains. After a few decades of that your faith in human nature is in the ground. It's a premature burial, predating your own."

The Garda, unfortunately, isn't done with him. In his new novel, Old God's Time, Sebastian Barry follows Tom as his life is thrown even further into disarray when he's confronted with a past he'd rather forget. It's a relentlessly bleak, stunning novel about how the effects of violence and abuse can reverberate for years and across generations.

Tom is mostly enjoying his retirement — being "stationary, happy and useless" — when he's visited by two Garda detectives who say they think he might be able to help them with a case. Tom takes an instant shine to them, and his first instinct is to offer his assistance, but he pales when the detectives tell him the case involves a priest who was murdered years before. "Jesus, go home, boys," he thinks. "You are bringing me back to I don't know where. The wretchedness of things. The filthy dark, the violence. Priests' hands. The silence ... The fullest humiliation of it felt afresh. Still present and correct, after all the years."

Tom is still haunted by the case. The priest in question was suspected of sexually abusing children, and Tom considered his death no great loss — he was abused as a child by a Catholic brother, and his late wife, June, was repeatedly raped by a priest when she was a little girl. Both suffered post-traumatic stress from the abuse. Tom recalls his wife's descent into emotional distance: "He had no way to reach her, even when she was home. She was a telephone not plugged in." He also remembers witnessing the sexual assault of boys — "with the light in their eyes put out" — at the hands of priests.

It's revealed early in the book that Tom is haunted by more than his childhood. The two children he and June raised have both died, although he at times imagines that both are still alive, with his daughter, Winnie, paying visits to him at his Dalkey home. Despite the anxiety and depression that visit him after the detectives come to his house — and his worsening memory — he agrees to help on the case when his old colleague, now a Garda chief, asks him to. Tom soon finds out that his involvement isn't exactly what he thought it would be.

Barry has always had a gift for creating memorable characters, and Tom is one of his most fascinating ones, in large part because of his unreliability. The novel is told from a third person limited perspective, and it becomes clear to the reader early in the novel that Tom, wracked with nearly unendurable trauma, doesn't know quite what's going on with his own life; it calls everything in the book — even the existence of some of the characters — into question. Tom admits as much: "He was clearly going mad. But he had read somewhere that the truly mad would never know they were mad. He knew he was mad. Was that a proof of sanity?"

Barry's prose is, as usual, wonderful. The writing, at times, borders on stream of consciousness, as Tom struggles to keep up with, and to avoid, his own thoughts. At one point, after the initial visit by the police detectives, Tom wonders if he's strong enough to withstand what his life would become: "Oh, oh the world was too difficult for him. It was. No. Wretched lie. Lying to himself, like a maniac, like a dark criminal with crimes too wretched to admit to, even to himself."

It likely goes without saying that Old God's Time can be immensely, almost physically painful to read; the novel contains descriptions of child sexual abuse that are unsparingly graphic. But Barry still approaches the topic with sensitivity — the scenes hurt to read, but in context, they feel necessary, refusing to let the reader escape from the kind of brutality that went unpunished for decades in Ireland and elsewhere.

Old God's Time is a powerful, painful novel, another excellent offering from Barry, who is clearly one of the best Irish writers working today. It's also a book suffused with a deep moral anger that refuses to let go of the crimes that destroyed the lives of so many. "People endured horrors, and then they couldn't talk about them," as Tom observes. "The real stories of the world were bedded in silence. The mortar was silence and the walls were sometimes impregnable."