Rudderless after betrayal by her former fiancé, Montreal heiress Sally Ryder discovers her dead mother had a secret life and she has an older half-sister. Helena has written to Sally inviting her to Midwinter, an isolated estate in Quebec. But Helena and her husband die meanwhile under disturbing circumstances. Too curious to stay away, Sally heads for Waverley anyway, and she isn't the only one. Wealthy Howard's spiteful will is the first shock. Soon everyone is snowed in, and murder arrives.