The Upgrade Apocalypse opens at a ten-year high school reunion interrupted by comet-delivered undead. A world-governing system activates, offering survivors skill cards and stat progression as the price of continued existence. The series leans into its premise's dark humor — old grudges, rekindled relationships, and petty social drama run in parallel with survival horror. Chedderfield and Archimedes anchor an ensemble of former classmates learning to fight.

The ensemble cast includes Chedderfield and Archimedes as anchors, but the series deliberately spreads its spotlight across multiple characters. No single hero carries the weight alone — death is on the table for anyone. The characters are defined more by their pre-apocalypse relationships and petty histories than by fantasy-hero archetypes, which gives the series a grounded, irreverent energy.

Across three books, the survivors evolve from panicking civilians to a ragtag force capable of taking on organized undead armies. The humor never fully recedes — jokes about the apocalypse, creative cursing, and character deaths used for comedic effect are hallmarks of the series' voice. By book 3, the Hell-Cursed have developed military organization and the survivors must form alliances and deal with old enemies to save their city.