Content Warning: The source material contains depictions of physical and sexual violence against minors. It also depicts suicide, drug abuse, acts of terrorism, violence, and murder.

Tom Kettle, a retired police officer, lives on the outskirts of a small Irish seaside town called Dalkey. He has been living here for nine months, after 40 years in the police force and a few years in the army prior to this. He rents an annex apartment from his wealthy landlord, Mr. Tomelty, who lives in a house that is an imitation of a Victorian castle. Tom hasn’t had much human interaction during these nine months. He usually spots Tomelty gardening, dressed in old clothes. The tenants downstairs are a young mother and child, and Tom rarely sees them. Tom’s next-door neighbor shoots the distant cormorants and gulls with a sniper rifle; he is a cellist and plays at all hours. Tom’s daughter Winnie visits, though his son Joe, a doctor in The United States, is too far away.

Unexpectedly, two police officers from his old division, O’Casey and Wilson, visit Tom one day. They say that Detective Superintendent Fleming has sent them to ask for his help.