In the East End of London, two brothers, Terry and Andy, decide to rob a bank to save their grandfather's retirement home from being demolished by property developers. Their seemingly simple plan quickly goes awry when they, along with their cousin Katy, a friend named Davey, and two hostages, find themselves caught in the middle of a zombie apocalypse. Unbeknownst to them, a construction site in the area has unearthed a centuries-old plague pit, releasing a horde of zombies upon the city.

As the group makes their escape from the bank, they must navigate the chaos of London overrun by the undead, trying to reach the safety of their grandfather's retirement home. Meanwhile, the grandfather, played with grizzled charm and veteran savvy, and his eccentric group of elderly friends find themselves under siege from the zombie horde. The convergence of the two groups sets the stage for a stand-off, with bats, guns, and good old-fashioned East End grit against the relentless tide of the undead. The mismatched band must band together, using their wits and weapons at hand, in a desperate fight for survival.