This old book looked too suspicious to ignore it, so you decided to read it. It was a big mistake as with your language you have summoned an army of zombies. Stop them or be eaten by the walking dead.
Are you ready to fight zombies? Of course not, it's scary, but you have to do that. Grab your pistol and click on the character to make him active and stop those zombies before they come in a close range. Can you stay alive in this madness and dodge their attacks? Play the game and test yourself completing levels one by one.