A Sudoku championship tournament has come to Kate McDonald’s small town in New Hampshire. She’s thrilled for the opportunity to raise the profile of the Avondale Puzzle Museum, now that she’s given up her think-tank career to restore the museum to its former glory.

But the puzzle world isn’t all quiet pencil scribblers. Intense rivalries are boiling over, the townspeople are facing off against the police, and a big storm is headed toward town.

Then the current champion is found dead in a snowbank, and suddenly everyone’s a suspect….and trapped in the town hall ‘til the storm blows over...