After leaving the bar one night, Mickey and Ben find a flyer stating to "call for free fun. Looking for a man who doesn't mind larger ladies." Mickey is skeptical, but quickly talked into it by his more adventurous friend.
After calling the number, they head over and let themselves in as instructed. They are startled by an old man, who introduces himself as Bessie's husband. He assures the two friends she is much younger than him, but things are no longer working properly for him "downstairs" and that he wants to make sure she's taken care of. He adds that he also loves to watch her be pleasured, but not to take any notice of him and to pretend he's not there. Even though Bessie didn't mention this on the phone, and they are hesitant to let the old man join in the room, they ultimately acquiesce.
What waits for the guys upstairs on the king mattress can only be described as a "behemoth," wearing a blindfold - but nonetheless, the drunk pair get down to business. Everything goes as expected, and in fact, Bessie quite enjoys her time with the two men, but they are very put off by her creepy husband and hightail it out of there.
The next day, Ben calls Mickey, frantic. He tells Mickey how he invited a girl over, and once they went to the bedroom and started to have sex, he felt the old man - who he calls "The Cuck," watching him. He says he looked in the corner and sure enough, the old man was there, watching them. Only, his date couldn't see him... And when they finished, the man simply vanished. Mickey doesn't know what to say or think, but when the exact same thing happens to him the next night, he knows something is very wrong.
-------------SPOILERS PAST THIS POINT--------------
The only thing the friends can think to do is ask Bessie, but when they get to her house, she tells them she doesn't even have a husband... What they are dealing with is far more than a man who enjoys watching his wife be pleasured by other men. The Cuck is not a man at all, but a demon, not unlike a parasite, which latches itself onto you typically during sexual acts that are more bizarre and extreme in nature. And anything sexual at all will summon it to you, once attached. Appearing in the room with you during sex to watch is only the beginning... Soon it begins to manipulate your mind and force you to mutilate your genitals.
Can the friends find a way to rid themselves of The Cuck, or are they doomed to a sexless existence?