It features a young couple, Alex (Stiller) and Nancy (Barrymore), who move into a brownstone duplex in Brooklyn, where an elderly tenant named Mrs. Connelly (Eileen Essell) starts giving them hell. She sends both of them on a myriad of errands, keeps them up all night (every night), gets them fired from their jobs, and lowers the value of the property with each passing day.
Since they can't get rid of the sweet old lady because of rent control, Alex and Nancy try to coerce her out of the apartment, eventually turning to less friendly methods... and getting clumsier and clumsier the more they escalate.
This film provides examples of:
- Bad Cop/Incompetent Cop: You start with Officer Dan who you think is just a unnecessarily violent Jerkass, but later you find it out it's intentional to scare Alex and Nancy into leaving.
- Bitch in Sheep's Clothing: Mrs. Connely. Not only is she a high-class slave driver that constantly pesters for help, but then it turns out that she is part of the scam... maybe even the leader.
- Butt-Monkey: Alex gets the absolute worst of the physical punishment amongst the couple, up to and including getting nearly shot with the spear gun. Well, he IS played by Ben Stiller.
- Cool Old Lady: Mrs. Connelly is an Irish seaman's widow with a parrot and a spear gun.
- Cringe Comedy: From the moment they get into the house, it's a barrage of misery so unending that they quite willingly decide to hire a hit-man to kill Mrs. Connely, because as long as she's alive and being a center point of said misery, it just doesn't looks like any options can really make it any worse.
- Harmless Electrocution: Barrymore's character, Nancy, tries to fix a faulty power plug on Mrs. Connelly's flat and gets electrocuted for it with the typical funny fro and being tossed a few feet backward. In her defense, she did asked Mrs. Connelly to shut down the power while she worked on it... only for her to turn it back on without warning Nancy.
- I Should Write a Book About This: The main character is trying and failing to write a book throughout the movie, mostly due to his upstairs tenant. The end of the movie shows his published novel, also titled Duplex, presumably about the events he experienced during the movie.
- Market-Based Title: The UK title is "Our House".
- Most Writers Are Writers: Alex is a writer. The horrors he suffers not only provide him a hefty amount of writer's block, but when he actually manages to power through Mrs. Connelly's constant pestering to finish his book, Mrs. Connelly accidentally tosses his laptop to the street where it gets run over by a truck, and he is unable to even try to get it fixed before his deadline, which gets him fired by his publisher.
- Narrator: Danny DeVito, who also directed the movie, is narrating it.
- Oireland: Mrs. Connelly, complete with bad Irish accent and one scene where she annoys Alex and Nancy by performing river dance upstairs.
- One-Word Title: In combination with The Place, one of its known titles is Duplex, about the duplex the characters live in.
- The Place: In combination with One-Word Title, one of its known titles is Duplex, about the duplex the characters live in, and the UK title is Our House, which is an example of this trope.
- Professional Killer: Chick the hitman, who has a legitimate job as a pornographer. He becomes important to the plot at the end when Alex and Nancy, fed up with Mrs. Connelly and seriously thinking it can't get any worse, sell all of the stuff they have remaining and drain their (critically low, thanks to Mrs. Connelly) bank accounts to be able to afford his fee.
- The Reveal: Mrs. Connelly is discovered to be both alive and in fact she is the mother of Kenneth, the Duplex real estate agent, and in fact it's a Real Estate Scam to make them sell the house cheaper then they bought it.