Not too long ago, a zombie disease had spread tremendously around the country. And it infected everyone. You are the only one non infected. Or so you thought.

You were at your tent guarding it when you got a sneak attack. The zombie didn't bite you but you were badly wounded, therefore, you passed out

When you woke up, you were in someone else's tent. And it wasn't yours. When you got up, you saw another person organizing weapons. He looked about your age.