At the tail end of the Roaring Twenties, a birthday bash for publishing heir John Sebastian, Jr., perfectly coincides with the twelve days of Christmas. Among the twelve invited guests is Ellery Queen, a newly published mystery writer planning to enjoy every last minute. But when an uninvited Santa Claus shows up on Christmas Eve and then mysteriously goes missing, the party takes a disturbing turn. Threatening clues masked as gifts begin to appear under the tree, and Queen - a novice crime fighter on his first solo case - must try to solve the killer's puzzle before someone gets murdered.

After a dead body turns up, Queen is no closer to stopping the killer. If he can't anticipate the next clue before it shows up, John Sebastian's birthday will end up his funeral.

From his first appearance in print in 1929, Ellery Queen became one of America's most famous and beloved fictional detectives. Over the course of nearly half a century, Frederic Dannay and Manfred B. Lee, the duo writing team known as Ellery Queen, won the prestigious Edgar Award multiple times, and their contributions to the mystery genre were recognized with a Grand Master Award, the highest honor bestowed by the Mystery Writers of America. Their fair-play mysteries won over fans due to their intricate puzzles that challenged the reader to solve the mystery alongside the brilliant detective. Queen's stories were among the first to dominate the earliest days of radio, film, and television. Ellery Queen's Mystery Magazine, which the writers founded and edited, became the world's most influential and acclaimed crime fiction magazine.