It's a mystery every month from A to Z Mysteries author Ron Roy!
Who knew there were 13 months in a year? It's an extra 13th book of the Calendar Mysteries!
Bradley, Brian, Nate, and Lucy are looking forward to a New Year's Eve party. But someone is leaving clues that there might be more to this celebration than confetti and noisemakers. The year ends with a surprise in this exciting conclusion to the Calendar Mysteries series.