The now-free Dead Kings add-on is making its way to PC, XO, and PS4 beginning January 13th, 2014. Here is some info direct from Ubisoft’s press release :
“In addition to a fully-fledged main single-player campaign, Assassin’s Creed Unity – Dead Kings also offers new open world activities and side missions, including new Murder Mysteries, enigmas and cooperative missions. Both single-player and cooperative modes enable players to unlock new weapons, gear and outfits that carry over between Assassin’s Creed Unity and Assassin’s Creed Unity – Dead Kings.”
Well, we can’t turn down the price tag, and look forward to next week’s DLC.