Henry fits in well. He runs errands for both the accountants and the advertising firm, and the women in the typing pool all joke with him. The second floor is a little odd because it seems cramped but spacious at the same time. Then a new company comes in to rent the 3rd floor. They're an Importing/Exporting firm but Henry never sees anything delivered to them so it must just be the office, with a warehouse somewhere else.
One day Henry is asked to go upstairs and by mistake goes to the 4th floor, which is there today. The lift doors open and he's greeted Liz from the typing pool. She asks him what he's doing there and and he says he made a mistake. She gives him a name tag with "Henry" on it, and tells him to follow her. The 4th floor seems to go on forever and everything is immensely bright. He can't see any windows and there seems to be a whole farm there and then they get to the "ocean". Another woman from the typing pool is there and greets them. The ocean is like a great pool that he can't see the end of, and in the strong light seems light grey.
In the distance Henry sees a figure. It's back-lit and he can only see the outline but it looks like a thin man with snakes for legs, and is gliding on the water. He points to this and Liz says "That's Davobah, the lord of this domain. Francine and I love him." Henry says back "Oh, OK!" Then Liz takes him back to the lift and he gets to the 3rd floor. Today it looks a bit different and all the furniture is gone and tall weeds are there instead.
One of the businessmen comes in, wearing a name tag of "Fredericks", and asks what he's doing. Henry apologizes and says he went to the 4th floor by mistake. The man looks at him and at the name tag that Henry's still wearing with a menacing expression, saying "So now you know how we export/import. Very well". Henry's a bit lost by this remark and carries on with his work. Later in the day when he has to deliver a telex to them and is just about to knock on the door he overhears their conversation. A voice says" This Henry's seen too much, we have to eliminate him" and Fredericks replies "Leave that to me. I'll take him on a tour of the interchange tomorrow and feed him to Davobah. I'll set up the sacrifice based on his name tag tonight." Henry quietly walks away and goes back downstairs.
In the morning Henry comes in very early, telling the doorman that he has to do overtime to fix up a mistake he made the day before. He immediately goes to the 3rd floor. No one's about at all, and he discovers a cork board with a dozen name tags pinned on it. He finds the one for Fredericks and carefully peels the name sticker from his own and from Fredericks, and swaps them around. Finally he takes Frederick's name tag with him, though now it has his name on.
Later Henry is summoned up to the 3rd floor and Fredericks says that as he already knows about "the back yard" that he's going to give Henry a proper tour, so that he can run errands there. Henry nods and off they go to the 4th floor. Liz isn't around this time and they go to the ocean. Henry sees the figure again and asks what t is. Fredericks says that it's 'DAVOBAH, demon of the endless sea', and that he's harmless. Davobah comes closer and closer and Fredericks tells Henry not to worry. Then Fredericks has a look of horrified surprise ad Davobah attacks and eats him. The demon then turns to Henry and says "HE WAS WELL OVERDUE FOR THAT - THIS BASTARD HAS CAUSED ME AND MINE TO SUFFER. THANK YOU HENRY". Henry tells Davobah that he's welcome and makes his excuses, and then goes to a pub and gets drunk. The next morning Henry comes into work and the entire building is burnt down. No one seems to know if anyone survived.
Twenty years pass by and Henry is now working as a "repo man" for a firm that specializes in repossessing electronic appliances. He and a work mate are called out to the the state housing flats where they have to repossess a 100" flat screen TV. They arrive at the flats and walk up the driveway. Henry sees a woman outside the flat they have to call at and recognizes her as Liz from the typing pool. He sees her knock on the door and a tall man comes out.
Henry turns to his colleague and tells him "I've got this one Jack, I know these people". Jack waits at the end of the driveway while Henry goes forward. As he gets closer the image of the man becomes wavy and there's a suggestion of snakes where his legs should be. Henry stops and says "No worries Dave - I've got this one!" He then turns around and says to Jack "I thought so, it's a mix up. They made the last three payments. I'll square this up at the office". And then Jack and Henry drive away...