Happenstance is a small town located in an underground ice-enclosed cavern. Two weeks before Christmas, everyone busily completes the final touches on shopping and planning attire, as well as practicing new dance steps for the dinner finale of the year. In anticipation of Santa's Christmas Eve ride, excitement seems to be everywhere ... until Uncle Hermes goes missing. The door to Mobil Land has been left ajar, and its interior is in shambles. These are not habits Uncle Hermes would abide. Robye Jax is the son of one of Happenstance's founders. From early childhood, he has been educated in the discipline of scientific expression, so he recognizes the signs. There is no question: the ice moles are on the move. Every twelve years, the ice moles migrate through the cavern walls to reproduce. Forming into colonies of thousands, they activate in sync and begin a chaotic activity called "whorling." The snow bobbies are capable of detecting the eminent whorling event, and they've been sending Robye frantic messages of warning. Oh, yes, Robye knows why Uncle Hermes has gone missing, and he now must get him back before Christmas is destroyed.