Having a party, he and his annoying friends decide to hold a séance, which is no fun at all as it unleashes a malevolent spirit trapped in the mirror who, ultimately, takes control of Warner, forcing him to kill again and again.
In time, when enough blood has been spilled, the spirit is able to leave the mirror and walk the earth. He is not in the least a nice man, and this concept is particularly unpleasant. To put the tin lid on it, poor old blood-stained Warner finds himself in the mirror world.
Years later, the new tenant of the flat has a party, and he and his annoying friends hold a séance, and the whole cycle begins again. Ulp.