As the scene unfolds during a night of dark nuptials, Morticia Addams (played by Charlize Theron) and Gomez Addams (portrayed by Oscar Isaac) face an unexpected disruption on their wedding day—a mob of intolerant individuals who scorn them as outsiders. Just when all seems lost, Gomez's brother Uncle Fester (played by Nick Kroll) and his mother Grandmama (brought to life by Bette Midler) arrive to shield their family from the unruly bunch. However, the commotion escalates to the point where Gomez and his family have no choice but to escape across a collapsing bridge.
Determined to find a place where they can thrive in their wonderful weirdness, the Addams family, along with their trusty hand Thing, embarks on a peculiar journey to New Jersey—an area known for its rejection of conventionality. Their adventure takes an odd twist when they encounter Lurch (voiced by Conrad Vernon), a towering figure recently freed from confinement. In what feels like destiny, they come across a decrepit asylum nestled on a hill, an eerie locale that by the sounds of “GET OOOOUUUUT!” beckons them to make it their home.
Fast forward thirteen years, and Gomez and Morticia have transformed the asylum into a delightfully macabre household filled with peculiar comforts. Their children, Wednesday Addams (voiced by Chloë Grace Moretz) and Pugsley Addams (played by Finn Wolfhard), flourish in this unique environment. The family's everyday routine is disrupted when a mysterious sound emanates from outside their gates, leading to an unexpected encounter with Parker (voiced by Elsie Fisher), an inquisitive young girl.
Pugsley prepares for his upcoming Mazurka, a cherished Addams family rite marking coming of age. Although his methods are unconventional, Gomez frets over Pugsley’s approach, yearning for adherence to tradition. As the Addams family comes together in anticipation of their guests, long-buried secrets begin to emerge, particularly when Uncle Fester intrudes during a family meal, following a prior explosion instigated by Pugsley’s antics.
Across town, Margaux Needler (voiced by Allison Janney), the radiant host of a home makeover show, finds her world disrupted by a visit from her daughter Parker. Eager to share her curiosities about noises from the mysterious hill, Parker is ignored by Margaux, who is ensnared in her ambition to perfect the town of Assimilation.
Meanwhile, Wednesday, ever the enigma, offers to assist Pugsley with his Mazurka preparations, albeit with sinister intentions as she fantasizes about entombing him alive. Her gaze drifts towards the preposterous perfection of Assimilation, where she is captivated by the festive balloons and unusual celebrations emanating from below. The family decides to venture into the town, accompanied by their loyal pet lion Kitty Kat. The response from the townsfolk is immediate; they are both fascinated and unsettled by the Addams' unconventional ways, culminating in a confrontation with Margaux Needler, who is caught between her intrigue and aversion.
The family's peculiar nature unfurls itself at the town's gathering, where children sing songs in praise of conformity. Just as the atmosphere becomes twinklingly chaotic, Fester loses his wits, unleashing a swarm of bats that send the locals into panic. Margaux sees an opportunity to gentrify the Addams mansion, suggesting renovations to Gomez and Morticia, who reluctantly agree believing they could use a modernization alongside their spooky charm.
The next morning, when Margaux and her dynamic crew show up at the Addams mansion, they are met by Parker, who attempts to breach the eccentric household but is swiftly turned away. A new friendship blooms when Wednesday and Parker find common ground over their dissatisfaction with life, leading them to explore Assimilation together.
Under the guise of home renovations, Margaux tries to swindle the Addamses, who are already content with their haunted abode. Despite the crew's hesitation driven by the house's quirky ambiance, Margaux remains undeterred, determined to inject her vision onto their lives.
As Wednesday uncovers the truth about her curious new friend, she embarks on a journey to Parker's school, navigating the unfamiliar social maze where she encounters bullies and unexpected camaraderie. In between, Grandmama re-enters their lives, bringing her unique flair to the household, much to Morticia’s bemusement.
In a cathartic twist of events, Wednesday and Parker find themselves discussing the pressures of parental expectations, prompting transformations that shock their mothers. Meanwhile, the family's stillness is disrupted by tech-savvy Margaux and her pernicious plans to eliminate the Addams family’s unique flair.
As tensions boil and the townsfolk unite against their supposed adversaries, the Addams children prepare for the crucial Mazurka. But in a shocking display of carnage courtesy of combustion-induced antics, the Addams family's essence emerges—showing love beneath their morbid layers.
With the armor of misunderstandings stripped away, the townspeople engage in an odyssey of reconciliation as they discover the Addams family's benevolence. By journey's end, Margaux's shortcomings are unveiled, leading to unexpected partnerships and tenacity as communities converge for harmonious cohabitation.
As the credits roll, these darkly whimsical characters snap together, capturing a picture-perfect moment—a concluding scene imbued with the essence of their morbid charm and the iconic theme song that has echoed through the halls of their storied legacy.
