The Lighthouse by P. D. James

On Combe Island, a remote and windswept refuge for the powerful and the famous, peace and privacy are guaranteed—until a high-profile guest is found hanging from the lighthouse tower. Commander Adam Dalgliesh and his team are sent to investigate, but what first appears to be a suicide quickly unravels into something far darker.

As the island is sealed off from the outside world, tensions rise among the small, privileged community trapped together. Every resident harbors secrets, and the line between guilt and innocence blurs. For Dalgliesh, the case becomes not only a search for a killer but a confrontation with the frailty of human motives and the isolation of the human soul.