In 1990, Joy Mangano, a struggling airline booking agent living in Peconic, New York, faces significant financial hardships while navigating a chaotic family dynamic. Under her roof, she balances the lives of her two children and her single mother, Terri, who spends her days glued to soap operas. The household is further crowded by her maternal grandmother, Mimi, and her ex-husband, Tony, an aspiring singer who takes refuge in the basement.
Adding to Joy's challenges is her ambitious half-sister, Peggy](/actor/mariam-sanusi), who is relentless in her taunts about Joy’s divorce struggles, making the already tumultuous family environment even more stressful. Joy's father, Rudy, complicates things further by moving into the basement after his third divorce.
Despite these obstacles, Joy finds encouragement from Mimi and her best friend, Jackie](/actor/angela-ekeleme), to pursue her dreams of inventing. This inspiration strikes when she grows frustrated with conventional mops, leading her to devise an innovative self-wringing mop design. Support arrives from a wealthy Italian widow named rudy, who is romantically involved with Rudy and chooses to invest in Joy's venture. They secure a low-cost manufacturing deal in California for the mop's components.
However, trouble looms when the manufacturer warns Joy of a potential patent conflict with a similar product in Hong Kong, suggesting she pay $50,000 in royalties. As the manufacturer begins to pressure Joy for additional payments due to faulty parts, she stands firm and refuses to comply.
In a pivotal moment, Joy teams up with QVC executive Neil Walker, who sees potential in her mop and agrees to feature it on television. To ramp up production, Joy takes out a second mortgage on her home to produce 50,000 more units. Her first television pitch falters when the celebrity promoting it fails to demonstrate its effectiveness properly. Determined to succeed, Joy insists on a second infomercial, which pays off spectacularly as the mop sells out, bringing in a substantial profit. However, this joy is bittersweet as she grapples with the loss of Mimi shortly after.
The trials continue as Joy’s burgeoning business faces disasters. When [Peggy unilaterally pays the manufacturer exorbitant charges without Joy's consent, the financial strain threatens to unravel Joy’s hard-won success. The manufacturer refuses any refunds, exploiting a contractual loophole to claim ownership of Joy's design.
As Joy recovers from filing for bankruptcy, shocking news surfaces: the alleged rival product in Hong Kong was a ruse, and the manufacturer had deceived her. With steely resolve, she confronts owner Derek Markham and demands repayment of the overcharges and rightful ownership of her patent or face legal consequences.
Emerging victorious, Joy transforms into a thriving independent entrepreneur, offering sponsorship to fellow inventors. Throughout this tumultuous journey, Jackie and Tony become her most trusted advisors. Despite supporting her ailing father and dealing with Peggy's failed lawsuit for her company, Joy presses on, while only Terri finds independence by partnering with Toussaint, a Haitian plumber. As predicted by Neil, their paths cross in the business realm as they become "adversaries in commerce" when Joy makes her move to HSN, yet their personal bond endures.
