Naughty Dog has revealed the first details on The Last of Us: Left Behind, the first piece of single-player DLC for this summer's hit survival adventure due for release in early 2014.

Set prior to the events of the full game, Left Behind tells the story of Ellie and best friend Riley (performed by actress Yaani King) as the pair attend a military boarding school in the Boston quarantine zone.

"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," said Naughty Dog, while confirming that players will play as Ellie throughout the entirety of the DLC.

Headed up by The Last of Us creative director Neil Druckmann and game director Bruce Straley, and with actress Ashley Johnson returning to reprise her role as Ellie, Naughty Dog promises that Left Behind will "meet the quality and gameplay what you've come to expect with The Last of Us, along with a few surprises".

Left Behind will be included for free in The Last of Us Season Pass and will be available to buy separately for $14.99. A UK price has yet to be confirmed.