User blog comment:Argorrath/Treyarch posts a message of zombies; possibly hinting to a DLC 4/@comment-98.233.126.228-20130802015134

My theory, however farfetched, is that the Rift will send the BO2 characters back in time to World War I France, where they will have the opportunity to somehow end the zombie threat once and for all by killing all the zombies before the outbreak. Instead of the rounds counting up, they'll somehow count down.

We'll get a cool feature where we're able to use WW2, Cold War and Future weapons all at once and somehow the Easter Egg will work in the original and new characters. One can only hope!