On Christmas Eve in 2001, Ethan Miller (Joseph Gordon-Levitt) faces the heartbreaking loss of his parents due to a tragic car accident. His steadfast friends, Isaac Greenberg (Seth Rogen) and Chris Roberts (Anthony Mackie), remain by his side, establishing a beloved tradition of spending every Christmas Eve together. Fast forward to 2008, the trio stumbles upon a mysterious woman at a bar who tantalizes them with tales of the wildest Christmas gathering known as The Nutcracker Ball. Determined to experience this legendary party, they embark on a quest over the next few years, yet their efforts prove fruitless.
Fast forward to 2015, Chris has found fame as a professional football player while quietly battling his own demons with performance-enhancing steroids. Isaac is settled in life, married to Betsy (Jillian Bell) and eagerly anticipating the arrival of his first child. Meanwhile, Ethan grapples with the end of his relationship with Diana (Lizzy Caplan) and finds himself working in a hotel dressed as an elf, enduring the frustrations of a demanding boss. One fateful day, while sorting coats, Ethan discovers something unexpected: three tickets to The Nutcracker Ball. Bursting with excitement, he rushes out, only to learn the event's location will be revealed at 10:00 PM.
As the evening unfolds, Isaac and Chris contemplate putting an end to their cherished tradition, feeling the weight of their evolving lives. This year, Betsy gifts Isaac a box containing a plethora of substances, igniting the night’s escapades. In a twist of fortune, Chris, whose promotional partnership with Red Bull provides lavish perks, arrives in luxury, ready to partake in the festivities. The trio kicks off the night dancing on the FAO Schwartz piano to Kanye West's "Runaway," and soon after, they connect with their old dealer, Mr. Green (Michael Shannon), to secure some weed to fuel their night.
An energetic karaoke session ensues where they belt out "Christmas in Hollis," but things take a chaotic turn when Isaac finds himself spiraling in the bathroom on a mix of drugs. As he juggles drinks at the bar with Diana and her friend Sarah ([Mindy Kaling]), his antics lead to some unintended consequences. Just when things get wild, Chris is swept into an unexpected romantic encounter while also dealing with his own challenges of maintaining friendships amidst fame.
As the clock ticks down to the party, the guys encounter numerous obstacles — an awkward reunion, a miscommunication over phones, and even unexpected detours involving a dramatic chase for stolen weed. Isaac's mind is further clouded by his hallucinatory experiences, culminating in a bizarre encounter during a church visit.
In the midst of the chaos, Ethan battles feelings of abandonment and insecurity, wrestling with his emotions as he navigates relationships and the holiday spirit. A phone call from Diana reminds him of the consequences of unresolved feelings. As the night progresses towards The Nutcracker Ball, the trio's journey leads to more revelry and unfortunate missteps, all laced with humor, camaraderie, and a hint of introspection.
With the dawn of Christmas morning, the friends find resolution among the chaos. Isaac receives a frantic call about his wife's labor, launching the group into a mad dash for the hospital — only to discover it’s a false alarm, indeed! They come to terms with their fears and insecurities, weaving the bonds of friendship tighter than ever.
In a final heartwarming twist, they embrace the true spirit of the holidays around Isaac’s newborn, reminding them of the importance of friendship and love. As they serenade the baby with "Christmas in Hollis," a narrator, Santa ([Tracy Morgan]), reveals that the true Christmas party is just beginning, connecting this amusing escapade into a heartfelt conclusion filled with laughter and joy.
