Black Ops 2 Origins - How To Upgrade Knife

Call of Duty: Black Ops II, also known as BO2 or BLOPS II, is a first-person shooter developed by Treyarch and published by Activision. This is the ninth main installment for the Call of Duty franchise, and was released on November 13, 2012.
The story takes place across two separate arcs, one recounting events in the 1980s, and the other following characters in the year 2025. Whilst it continues the saga of certain main characters introduced in the original Black Ops, both arcs take place several decades after the conclusion of the first game.