Apocalypse Scenaroi #683: The Box by Mira Grant
I love the Mira Grant books about the zombie apocalypse. Mira Grant is also Seanin McGuire. This is a short story of about 14 pages in length. It follows a group of friends that may not know as much about one of their friends as they thought they did. The information they're missing may mean their doom. It'll take you seconds to read.