Murder Is Easy by Agatha Christie

In a quaint English village, a chance encounter on a train leads ex-policeman Luke Fitzwilliam into a web of intrigue and murder. An elderly woman confides in him about a series of "accidental" deaths she believes are deliberate murders, but before she can reveal the killer's identity, she herself is found dead. Driven by curiosity and a sense of justice, Luke travels to the village to investigate, uncovering a tapestry of secrets, lies, and hidden motives. As he delves deeper, he realizes that the seemingly peaceful village harbors a cunning murderer who will stop at nothing to protect their identity.