In the final book of the series, we go back to where it all started: Alex & Mickey in Tucson. With temperatures still falling, the survivors are forced to decide what to do with a rapist amongst them. But when Alex takes unilateral action, he risks his tenuous hold on the town. Leaving the town to stew over his actions, Alex decides to take a trip down to the impact site to see it for himself. Things go sideways when he finds he is not alone in the crater. From there, things only unravel in ways that Alex & Mickey could never have predicted. Struggling to keep it all together, they find themselves racing the devil to an icy future.

Written as a historical mockumentary a hundred years after the rebirth of civilization, Calizona gives the reader a granular view into the life of a citizen struggling to survive in the weeks and months following an extinction level event.