As the townsfolk of the Welsh valley town of Llanelen settle in for the snowiest winter in 25 years, an American stranger arrives. Harry Saunders charms the ladies and convinces Evelyn Lloyd, a wealthy widow, to invest money with him. When he goes missing with her money his body is soon discovered with a letter opener belonging to Mrs. Lloyd in his back. It's up to Penny Brannigan to prove her innocence.