Rick Grimes and the survivors he has led to Washington have been living for some time in a fenced compound on the outskirts of Washington, D.C. Rick has taken on the responsibility for his new community as a police officer, his son Carl has made new friends, Glenn conducts search missions into the depopulated city, and Carol keeps watch over the community. Daily life in the post-apocalypse is settling in. However, more and more undead from the former seat of the U.S. government are gathering at the gates of the compound. A small mistake, a moment of inattention, a breach in the fence, and everything turns into a single nightmare.