Finally got a story. Its a little more intense than typical zombies:
What the players know:
Your with american special forces. You speak some-what fluent japanese and you've just gotten seperated from your group and captured in japan.
What the players don't know yet:
You find a research complex, and realize time travelers have brought back super-futuristic weapons to the japanese. The only problem is they've brought a zombie-disease with them. So.... Super-Future Weapons, AND zombies. What more could you want?