In an American city during the early 1900s, Jim Dear presents his new wife Darling with a cocker spaniel puppy in a hatbox. They name her “Lady” and furnish her with a bed in the spare room, but as soon as they retire to their bedroom, the lonely puppy cries. Despite Jim Dear’s scolding and the huge staircase that she must surmount, Lady is determined to join them upstairs, and is soon allowed in their bed “just for tonight.” Six months later, Lady is still allowed in the bed, and enjoys her pampered lifestyle with her beloved owners. One day, she is given a license and collar, and rushes to display her new finery to her neighborhood friends, Scottish terrier Jock and elderly hound Trusty. Both admire her “badge of respectability,” and consider her life complete. Meanwhile, nearby a mongrel dog named Tramp enjoys a life of unfettered ease, disturbed only by the dogcatchers who impound all dogs without licenses. One day, when Tramp discovers his friends Peg, a Pekingese, and bulldog Bull in the dog wagon, he releases them and evades the dogcatcher by fleeing into Lady’s upper-class neighborhood. There, Jock and Trusty are consoling Lady, who is convinced her owners no longer love her. After she describes their symptoms, which include knitting booties and acting skittishly, the older dogs realize that Darling is expecting and try to explain “the birds and the bees” to Lady. Just then, Tramp joins them and angers Lady by declaring that her humans will have only enough room in their hearts for the baby. Months pass, during which Lady’s household readies for the baby, which arrives in April. Lady wonders what could be so special about the little boy until she sees him, after which she adores him as much as his parents do. The newly expanded family lives peacefully until one day Jim Dear and Darling decide to go away for the weekend and leave Aunt Sarah to baby-sit. Aunt Sarah, who has two wily Siamese cats, Si and Am, despises dogs and considers Lady a danger to the baby. After Si and Am wreak havoc in the living room, Lady tries to maintain order but receives only a scolding from Aunt Sarah. The next day, when Aunt Sarah brings Lady to a pet store and fits her with a muzzle, Lady recoils and races out of the shop. The muzzle and its attached leash attract the attention of three mean dogs, who chase her into an alleyway. There, Tramp spots the commotion and bravely rushes to Lady’s defense. After chasing off the dogs, Tramp brings Lady to the zoo, which does not allow dogs, in order to find someone to remove the muzzle. At the gate, he cleverly creates a hubbub that allows them to slip inside unnoticed. They soon find a beaver, and when he declares himself too busy moving logs to help, Tramp declares the muzzle a “log puller” and convinces the beaver to bite it off of Lady’s snout. Dubbing Lady “Pidge,” Tramp shows her the city, singing the praises of his “footloose and collar free” lifestyle. He brings her to Joe’s restaurant, where Joe, recognizing Lady’s pedigree, prepares a romantic meal of spaghetti and meatballs. While enjoying their dinner, Lady and Tramp unintentionally begin eating opposite ends of the same piece of pasta, realizing only after their lips meet in an impromptu kiss. Later, they walk through the park in the moonlight and sleep in the open air. In the morning, Lady wants to rush home, but Tramp urges her to see the world with him. When Lady reluctantly insists that she must watch the baby, Tramp leads her home, but along the way convinces her to stop to chase some chickens. As a result, they are shot at by a farmer and, upon escaping into the street, Lady is captured by the dogcatchers. She is brought to the pound, where the other inmates admire her license, calling it “a passage to freedom.” They are planning a prison break, hoping to avoid the fate of Nutsy, who is being put to sleep. Later, as the dogs discuss Tramp’s womanizing, Peg states that if he were tamed by a woman, he would instantly become vulnerable to the dogcatcher. Aunt Sarah soon brings Lady home but ties her up in the doghouse outside. The next day, Tramp shows up just as Jock and Trusty are each proposing to Lady in order to furnish her with a kinder family. Lady turns her back on Tramp, more angry about his long list of girl friends than about her time in the pound. As Tramp retreats, Lady spots a rat scurrying through the yard and tries to attack it. Aunt Sarah hears her barking and opens the nursery window, inadvertently letting the rat inside. Tramp returns to help, rushing into the nursery, where he topples the cradle while killing the rat behind the window drape. Lady manages to break free and rushes upstairs to check on the baby, who is unharmed. Aunt Sarah, however, rushes in and disturbs the baby, then blames his crying on the dogs. She locks up Lady and calls the dogcatcher to impound Tramp. Just as Tramp is loaded into the wagon, Jim Dear and Darling return and free Lady, who shows them the body of the rat. Realizing that Tramp was protecting the baby, they take Lady in the car and follow the dogcatchers. At the same time, Jock and Trusty comprehend that they have misjudged Tramp and set off to stop the wagon, and even though Trusty long ago lost his sense of smell, he regains it now. He heroically tracks the wagon and knocks it over just as Lady arrives, but her joy in rescuing Tramp is tempered by seeing Trusty pinned under the wagon’s wheel. Months later, Lady and Tramp are not only married but the proud parents of four puppies. They, along with Jim Dear and Darling and the baby, are thrilled to receive a visit from Jock and Trusty, who is now sporting a leg cast.