The Walking Dead: 400 Days is a special DLC for the award-winning adventure series from Telltale Games.
Read up on Susan Arendt's spoiler-free review here:
[quote]I'm not really going to tell you much about 400 Days, DLC for Season One of the award-winning The Walking Dead. I know that kind of defeats the purpose of of a preview, but I don't want to spoil anything about the story, the five new characters featured, or how their fates might (or might not) intersect with those of the survivors we already know. Here's the simplest version of what you need to know: If you played The Waking Dead, you will want to get 400 Days when it comes out in July. </qoute>