Pop superstar Kat Valdez (Jennifer Lopez), an iconic figure in the Latin music scene, has experienced the heartbreak of two highly publicized failed marriages. Following the success of her latest hit, Marry Me, a collaboration with her fiancé Bastian (Maluma), Kat plans to celebrate their love by tying the knot live in front of a global audience during one of her concert performances. Her dedicated manager Colin Calloway (John Bradley) is by her side, overseeing the event’s logistics.
On the other side of the spectrum, Charlie Gilbert (Owen Wilson), a recently divorced math teacher, is coaxed into attending Kat's concert by his friend Parker (Sarah Silverman) and his daughter Lou (Chloe Coleman), who has grown increasingly indifferent towards him. In an effort to bond with Lou, Charlie agrees to join them at the concert, hoping it will elevate his status as a fun dad.
However, just as Kat is set to exchange vows with Bastian, shocking revelations about his infidelities surface, creating chaos and heartbreak. In a moment of impulsive desperation, she spots Charlie in the audience, holding a sign that reads "Marry Me." To his astonishment, Kat decides to marry Charlie right then and there, amidst a flurry of media frenzy. The newlyweds leave the stage under a cloud of confusion, as Kat faces the reality of her crumbled engagement.
Following this whirlwind marriage, Kat makes a surprising decision—to maintain her union with Charlie for a few months, hoping to spin the narrative positively amidst the tabloids’ invasive scrutiny. Colin supports her but urges caution, while Charlie feels he is merely assisting someone in distress. They engage in a series of public appearances, presenting a united front, all the while grappling with the evolving nature of their relationship.
As they begin to interact without the media's interference, genuine connections start to blossom. Charlie shares his daughter Lou’s struggles with math, stemming from traumatic experiences, and Kat invites him and his students to enjoy a day of fun. She aids Lou in conquering her fears through dance and rallies the students for their upcoming Mathalon.
Their bond deepens into a romantic relationship as they share meaningful moments, including a special night where they kiss for the first time. Nevertheless, looming insecurities about Charlie's compatibility with Kat's glamorous lifestyle surface when Bastian reenters the picture, prompting Charlie to end their relationship.
Unbeknownst to Charlie, Kat transforms her emotions into a heartfelt song titled On My Way, which eclipses the success of Marry Me. Just before the Mathalon, while promoting her song on The Tonight Show, she clarifies that her heart lies with Charlie and not Bastian. In a race against time, she rushes to the Mathalon, where she finds Charlie supporting Lou. With a heartfelt gesture, Kat holds up a sign asking Charlie to marry her once more, leading him to joyfully accept her proposal.
Ultimately, Kat, Charlie, and Lou forge a loving family, alongside their dog, amid a backdrop of genuine companionship. The film concludes with a heartwarming montage, highlighting various couples sharing their unique love stories and how they met, celebrating the beautiful unpredictability of love.
