The final piece of downloadable content for Call of Duty: Black Ops II contains a new Zombies campaign that explains the outbreak's origins.

Apocalypse is set in a dieselpunk version of World War I-era France, and will pit players against a "1000-foot tall robot abomination" while they seek the truth behind the undead Nazi scourge.

The DLC will also feature four new multiplayer maps, including remakes of Black Ops' "Stadium" and World at War's "Courtyard".

Apocalypse will be available on Xbox 360 from August 28 for 1200 Microsoft Points.

PlayStation 3 and Windows PC versions will follow in September.