Trevor and Graham live very ordinary lives. Except of course when they inhabit their alter egos, Casimir and Sir Brandt, characters from the fantasy war games they play in Graham's basement and Trevor's allotment shed. In those they really are the heroes they imagine themselves to be. So when a neighbour's murderous activities unfortunately coincide with the zombie apocalypse, Graham and Trevor set off on a quest to save the women in their lives, and therein try to live up to the mantle of 'hero'.