Liza Kelly, Sudoku Maven with the Oregon Daily, is conducting a sudoku class in the most unlikely of locales: the minimum security wing of the Oregon Coastal Penitentiary. The students are eager for the distraction—they have too much time on their hands. And some of them are surprisingly good at their lessons. Though she’s sad when her best student has to quit the class, Liza is thrilled because he’s about to be released from prison.
But he doesn’t enjoy his freedom for long. His dead body turns up in Liza’s rented room during a snowbound weekend with her beau. With the police and an insurance investigator hounding her for information, and a rising threat that she or someone she loves could be the next victim, Liza believes her only solution to this murder is sudoku—and the secrets her clever student encoded into the seventeen-clue puzzle he created just before he died.