Every Mother's Day, robots made in Mom's Friendly Robot Company factories around the world give gifts, money and cards to the owner of the corporation, Mom. However, this year, Mom, bitter about a romantic affair that had ended 70 years prior, orders the entire robot population of Earth to rebel and overthrow humanity through a control that transmits to every robot's antenna. This doomed romance had been with a younger Professor Hubert Farnsworth, then an employee of Mom's Friendly Robot Company. When Mom insisted that the Professor's latest design, a children's toy named Q.T. McWhiskers, be changed to an eight-foot-tall death machine to be sold on the intergalactic arms market, the Professor, enraged, stormed out of the room, and they hadn't seen each other since.
Wishing to end the robot rebellion and save humanity, Mom's three sons, Walt, Larry, and Ignar, cooperate with the Planet Express crew to obtain the robot control Mom keeps in her bra. Their plan is to bring Mom to her rustic cabin in the Bronx, have the Professor seduce her, remove her bra, and use the control to end the rebellion. They give the crew a valuable non-computer-drawn map to their destination. Because of the distance, Fry builds a wagon (with oval wheels) to carry the Professor, but is then forced to pull it to the cabin.
When the Professor and Mom do meet, however, their love is rekindled, and they erupt into sex. Amidst this, everyone else comes in to escape the robots, who have made their way to the Bronx. Mom decides to call off the rebellion, but her bra is nowhere to be found. After searching, it is found to be hanging on a robotic fan which refuses to return it. Fortunately, Bender arrives and Mom asks him to recover her bra. While he initially refuses, when his card states that in the post-rebellion "robot worker's paradise" there will be no liquor, Bender angrily destroys the card and fetches the bra from the fan.
Mom uses the remote control to stop the rebellion, but dumps the Professor after learning of their plot. Life is then returned to normal. In order for the Professor to remember Mom, he sends out his albino shouting gorillas to yell her name.