Best. Christmas. Ever.

As the snowflakes gently fall outside, the Sanders family finds themselves cozied up in their small apartment, surrounded by the quiet desperation of a modest life. Charlotte and her husband Rob, feeling like they're stuck in neutral, can't help but be consumed by envy as they read Jackie Jennings' annual Christmas letter - a glowing report card on her seemingly perfect life. Jackie's tales of extraordinary achievements only serve to highlight the Sanders' own lackluster accomplishments: Dora's fixation on Marvel comics, Grant's attachment to his trusty stuffed monkey, Rob's harebrained scheme to flip houses, and Charlotte's abandoned dreams of inventing something remarkable.

When Grant misunderstands his mother's sarcasm and convinces the family to join him at the Jennings' home for Christmas, they find themselves snowed in and forced to confront their own insecurities. As the night wears on, Charlotte's suspicions about Jackie's perfect life grow, fueled by her misgivings about Jackie's fit, Latino husband Valentino. Her distrust leads her down a path of snooping, as she tries to uncover the secrets behind the Jennings' extraordinary achievements.

Meanwhile, the kids - Dora and Grant - are busy concocting their own misguided mission to expose the mall Santa, which ultimately culminates in a confrontational scene that leaves everyone shaken. Charlotte's accusations against Jackie and Rob, sparked by her misinterpretation of a harmless tradition, only serve to further strain their relationships.

As the film hurtles towards its climax, an elaborate solar-powered hot air balloon takes center stage - a poignant tribute to Jackie's late son Daniel. A series of events unfolds, culminating in a Christmas pageant spectacle that finds Santa's sleigh accidentally attached to the balloon. The absurdity of it all serves as a powerful reminder of the importance of embracing our quirks and imperfections.

In the film's epilogue, the Sanders and Jennings families come together to pen a joint Christmas letter - a heartwarming celebration of their newfound understanding and appreciation for each other's unique strengths and weaknesses. Charlotte boasts about her latest invention, while the Jennings promote their non-governmental organization (NGO) through their solar-powered hot air balloon travel, serving as a testament to the power of community and collaboration.