It's winter in northwest lower Michigan, which means librarian Minnie Niswander and her cat, Eddie, are staying cosy in the bookmobile. But not everything is as it should be. When an elderly housebound patron, Gerald Arnold, fails to answer his door, Minnie knows something is wrong. Her fears are confirmed when the police discover Gerald's body beneath the surface of a small frozen lake. Minnie knows that the kind and cautious Gerald would never have been so careless as to fall through the ice, and she suspects foul play. But law enforcement rules the old man's death an accident, and Minnie knows she will have to take the investigation into her own hands. As she and Eddie dig deeper, Minnie is troubled to learn that Gerald - and many of her friends - had been suspects in a decades-old cold case. Were the two murders connected? If so, it looks like justice is long overdue.