In 1957, the story unfolds around an ambitious songwriter named Roger Radcliffe, who resides in a cozy bachelor flat close to Regent's Park in London, accompanied by his beloved pet Dalmatian, Pongo. Feeling a bit lonesome, they both desire companionship. One day, Pongo keenly observes the interactions between various women and their dogs, and among them, he spots a charming young woman named Anita along with her own Dalmatian, Perdita. With a dash of determination, Pongo leads Roger to the park for a fateful meeting, which results in Roger and Anita falling head over heels in love. Before long, they tie the knot, with Pongo and Perdita joyfully attending the ceremony as the couple embarks on their life together.
After their marriage, the Radcliffes decide to hire a nanny and settle down in a quaint townhouse not far from Regent’s Park. Soon enough, Perdita finds herself expecting a litter of fifteen adorable puppies. However, trouble brews when Anita's former schoolmate, the fur-obsessed and sinister Cruella de Vil, arrives, inquiring eagerly about the puppies' arrival. In a cheeky reply, Roger creates a jazzy tune that pokes fun at her obsession. Meanwhile, Perdita, filled with trepidation, confides in Pongo, admitting her regret regarding the idea of having puppies given Cruella's greedy intentions.
When the eagerly awaited puppies finally arrive, Cruella reemerges, relentless in her desire to purchase them. Roger, standing firm, flatly denies her offer, which only fuels Cruella's fury. She storms out, vowing revenge on the couple.
In a shocking turn of events, Cruella makes her move by secretly hiring two criminal brothers, Jasper and Horace Badun, to execute her wicked scheme of stealing the puppies. As weeks pass and the pups go missing, Scotland Yard is unable to find any leads about their whereabouts or prove Cruella's involvement. In a desperate measure, Pongo and Perdita activate the "Twilight Bark," a canine gossip network, to rally support from their dog friends across London and eventually, all of England.
At a quaint far-off farm owned by a retired cavalry officer, known as the Colonel, an old English Sheepdog along with his feline friend, Sergeant Tibbs, investigates the eerie "Old De Vil Place," where they overheard puppies barking a couple of nights prior. Tibbs bravely discovers the puppies imprisoned in the old mansion and overhears Cruella's vile intention to turn them into fashionable fur coats. He immediately relays this critical information back to London, prompting Pongo and Perdita to embark on a treacherous journey across the countryside. They navigate through perilous icy rivers and aggressive snowstorms toward Suffolk.
Meanwhile, Tibbs overhears Cruella’s chilling orders to the Baduns about eradicating the puppies that very night, fearing that their capture by the police is imminent. In an act of bravery, Tibbs orchestrates an escape for the puppies through a wall, but the Baduns notice and give chase. In a climactic showdown, Pongo and Perdita manage to break into the house just as the Baduns are about to take the lives of the innocent puppies. In a fierce confrontation with the burglars, Pongo and Perdita battle to protect their offspring while the Colonel and Tibbs guide the puppies to freedom.
After a heartfelt reunion with their puppies, Pongo and Perdita are left astounded to find that there are 84 additional puppies in their care. Realizing the gravity of Cruella's sinister plan, they decide to adopt every last one, convinced that Roger and Anita would never turn away these furry friends.
Their adventure continues as the Dalmatians begin their journey home, with the persistent Baduns hot on their tails. Seeking shelter from a relentless blizzard, they find refuge on a dairy farm, aided by a friendly collie and four kind cows. As they make their way to Dinsford, they meet a Black Labrador who assists them amid the chaos. In a clever move to evade detection, Pongo's entire family rolls in the soot of a fireplace to disguise themselves as Labradors when Cruella and the Baduns close in on them. However, their cover is blown when melting snow reveals Lucky's true identity.
In a fit of rage, Cruella chases after the van carrying the Dalmatians, attempting to ram it off the road. In a disastrous twist, the Baduns inadvertently collide with her car, leaving Cruella and her minions stranded in a ditch, their plans in ruin. As she weeps over her losses, Jasper tells her to calm down, while the Dalmatians make their escape.
Back in London, a gloomy Nanny and the Radcliffes attempt to make the best of Christmas despite their hearts feeling heavy. Amidst their struggles, joy breaks through when Pongo and the soot-covered Dalmatians suddenly flood their home. Upon revealing the true number of their new canine family members, Roger decides to invest his songwriting royalties into purchasing a spacious house in the countryside, ensuring that they can comfortably accommodate all 101 Dalmatians.
