The storyline in "Call of Duty Black Ops 2"'s Zombie mode revolves around Edward Richtofen after the events of the moon DLC from "Call of Duty Black Ops." The story mode, titled Tranzit, allows players to attempt to solve the mystery of why the Earth is dying while fighting through endless hordes of zombies. The player receives assistance from both Richtofen and Dr. Maxis.
According to the official "Call of Duty" website, while the Zombie mode of "Call of Duty" does have a story arc, it is not a campaign due to its endless feature. Even the Tranzit mode in "Black Ops 2," while it focuses on the story aspects, is primarily a score-based game. "Black Ops 2" has four different Zombie modes. Tranzit is an endless horde of zombies with various story aspects and an open world. Survival mode takes place in a specific segment of the Tranzit open world and pits the players against an endless horde. Grief mode pits teams of four human players against each other as well as against zombies. Players can choose to fight one another or attempt to use zombies to their advantage. Finally, custom games allow the players to adjust the types of items, ways to kill zombies and time limit of their game.