A brief synopsis of Activision's near-invisible FPS has been published by the US store. Not much in the way of detail, but for what it's worth, Here's the description blurb in full:
UPDATE: Amazon US now has it down for pre-order, no such luck on the UK page:
"Before the future could be won, history had to be written. Exposing that story exclusively on PlayStation Vita, Call of Duty: Black Ops Declassified explores original fiction in the Call of Duty Black Ops universe with an all-new campaign of Special Ops missions. Optimized for gamers on-the-go, Call of Duty Black Ops: Declassified delivers the most intense handheld Call of Duty experience to date, including both Special Ops Story mode and Multiplayer combat tailored for the PS Vita."