When Sam Ward discovers his stag weekend is a mock zombie survival experience, he couldn't be more chuffed - after all, what better way to spend your last few days of freedom than running around the woods with your friends, shooting 'zombies' with paintballs?

But when the stag party arrives to find the 'zombies' are in fact a bunch of psychotic ex-soldiers, their fantasy weekend quickly starts to look like a nightmare.

After a series of unfortunate mishaps they find themselves trapped in a disused nuclear bunker, besieged by crazed, bloodthirsty 'zombies'.

Is it still just a game, or is it actually game over?