Naughty Dog revealed their upcoming single-player DLC for their PS3 survival action title, The Last of Us, during the PS4 All Access show last night. Dubbed "Left Behind", the new DLC features Ellie and her best friend Riley and tests the bond between them. As described on the PlayStation Blog: "Joining Ellie on this new adventure is Riley, her best friend and also a mentor of sorts at the military boarding school. Just as The Last of Us focused on the bond between Ellie and Joel, Left Behind explores the bond between Ellie and Riley through a series of events that will forever change both of their lives."
The announcement also included a reveal video, which can be viewed above.
The Last of Us: Left Behind will be released in early 2014. If that's too long to wait, the PlayStation Blog also suggests reading The Last of Us: American Dreams, a comic series by Dark Horse that tells the story of how Ellie and Riley became friends.