The Venice Train by Georges Simenon

The story follows Justin Calmar, an ordinary man whose life takes an unexpected turn during a train journey from Venice to Paris. After a chance encounter with a stranger who entrusts him with a mysterious package, Justin finds himself embroiled in a web of intrigue and danger. As he navigates the complexities of this unforeseen predicament, he grapples with moral dilemmas and the consequences of his decisions, ultimately leading to a suspenseful exploration of human nature and the thin line between normalcy and chaos.