Immediately after the publication of his first novel, detailing his investigation and solution of The Roman Hat Mystery, fledgling author Ellery Queen is invited to a house party to be held over the Christmas holiday period (late 1929 and early 1930) by his publisher. The party is large and contains a number of people connected for business or social reasons with a wealthy young man who is about to come into a large inheritance on his imminent birthday. In the days leading up to his birthday, a number of strange little gifts are left anonymously for him, one, two or three daily, together with some cryptic notes describing them. The gifts are sized as for a doll's house and are things like a tiny house, a post, a camel, a fish, an eye, a fence -- seemingly without any rhyme or reason behind them. The cryptic notes become more and more threatening and ominous, and some of them have little doodles on the back that seem to represent the gift associated with them. Ellery continues to investigate, with little success, as the mysterious gifts accumulate and the wealthy young man's behaviour becomes more and more unusual. Upon the eve of his birthday, his body is discovered stabbed with an ornate dagger, and a note beside it suggests that the dagger is the final entry in the series of gifts: "the finishing stroke to end your life". Although a number of things are discovered that explain parts of the mystery, Ellery is unable to explain the meaning of the series of gifts, or conclusively identify the murderer. Decades later, he comes across his diary of that time and begins thinking about the murder again -- this time, he realizes the significance of the gifts and can thus finally solve the case.