The Ricardos and Mertzes are having a late-night singalong to honor their great friendship. When the Mertzes go home, Lucy and Ricky keep on singing. They soon get complaints from the Mertzes, who only minutes ago were happily singing with the Ricardos. Now that the Mertzes want to sleep, they don't want the Ricardos making noise. Further tension between the couples escalates when the Mertzes are bothered by Lucy and Ricky slamming the bedroom window open and shut and by Ricky trying to fix a leak in the plumbing.
The Ricardos get so mad that they plan to move out as soon as possible. But they forgot that they have a lease, and the Mertzes refuse to let them out of their lease for free, just to be spiteful. So, Lucy and Ricky start a devious mission to "break the lease," by being as loud and obnoxious as possible. They stomp around the apartment, shout while speaking, use a rivet gun to pound lids of trash cans on the floor, and slam furniture.
To step it up a notch, Lucy tells Ricky to have his band have a noisy rehearsal that night l in the apartment. Even the cacophony of a full orchestra doesn't change the Mertzes' mind at first. Instead, they went out on the street and sold tickets to the performance. But when Lucy and Ricky have all of the ticket-buying guests dance loudly to a number Lucy entitles "El Break-o the Lease-o," the Mertzes can't fight any longer. Part of their ceiling caved in, and they enter the Ricardos' apartment to give up the lease covered in plaster.
The next scene shows Lucy and Ricky packing up their apartment, in preparation for moving. They find a picture they took on vacation with the Mertzes, Ricky finds some tools he borrowed from Fred, and Lucy remarks that she and Ethel also still have some of each others' things. The Mertzes come up to return items they have that belong to the Ricardos, and during this exchange, Lucy and Ethel break into tears and hug and make up. Fred and Ricky make up, too, only giving much less emotion, as a way to keep their pride. Fred then pulls out a new lease, revealing that he and Ethel had really come upstairs to reconcile all along.
- The argument between Lucy and Ricky about keeping the window open or closed came from a real-life dispute betwen Lucy and Desi. Lucy always was hot and wanted the window open, whereas Desi always was cold and wanted the window shut.
- This is the first time "Sweet Sue" is sung on the show.
- No reason is given as to why Ethel took her wedding ring off to play the piano. It's no wonder she left them at the Ricardos'. This is the first time it's ever joked about that Fred found Ethel's wedding ring inside a box of Cracker Jack.
- The previous summer, the Ricardos and the Mertzes went on vacation together up at Atlantic City.
- "El Break-o the Lease-o" is really titled "La Raspa," better known as "The Mexican Hat Dance."
- This is the first of many fights between the Mertzes and the Ricardos.
- Lucy and Desi had a very difficult time keeping a straight face when Bill Frawley and Vivian Vance entered the apartment with the ceiling plaster all over them. Look at their expressions- they're trying their best not to lose it.
- The plaster on Bill and Viv seems to have been attached by Velcro. When Viv crosses her arms, part of the plaster on her left shoulder falls down, and underneath is a material that looks like Velcro.
- In the final scene, when Lucy's packing up the apartment, there's a magazine on the coffee table that has a picture of Lucy and Desi on the cover.
Ricky: We're not making noise, we're making music.
Fred: Yeah, let 'em phone the landlord. I'm not home!
- Ethel: It will take the next five months' rent [from paying off the lease] to redecorate.
Ethel: Yes, AFTER we fumigate...
- Lucy: (making prank call to Ethel) Hello, this is the Ajax Salvage Company. We buy old glass. I understand you have some rings you're interested in selling, huh?