The story follows a group of survivors led by Rick Grimes (played by Andrew Lincoln), a former sheriff's deputy, as they navigate a world overrun by zombies, referred to as "walkers." As the group struggles to survive, they also face challenges from other groups of survivors, as human conflicts often prove to be more dangerous than the walkers themselves. The show explores themes of survival, morality, leadership, and the breakdown of society in the face of a global catastrophe.