In the heart of New York City, the life of young Gio is turned upside down when his father, Sam, is murdered, leaving his mother, Sofia, in a perpetual state of despair as she refuses to get out of bed. Seeking solace and distraction, Gio decides to take food brought by well-wishers to the local church.
Meanwhile, Gio's cousin Leo, who is with Uncle Ricardo, encounters a suspicious man with several bikes. Not satisfied with the man's response, Ricardo abruptly stops the car and aggressively confronts him. Within the church, Gio lights a candle and shares his troubles with Father Kelly, detailing an incident where he was bullied by some Russian kids at school. After their conversation, Gio exits the church, bracing himself against the cold snow predicted by the weather, and is just in time for Leo, who offers him a jacket.
As they stroll together, they confront the Russian bullies again, and Leo provides Gio with a gun, causing most of the gang to flee—except for one, who stands his ground. Fast forward ten years, and Gio is preparing for a family celebration. While Christmas decorations fill the air with cheer, the occasion is bittersweet as it marks the tenth anniversary of his father's death. Sofia, still gravely affected, is reluctant to participate but does present Gio with the traditional birthday cake she bakes every year. Amid her reflections, she expresses regret about Leo's detachment from the family and scolds Uncle Angelo for not maintaining contact with relatives. She insists Gio visit the church that night to light another candle.
As Father Kelly's familiar voice punctuates the narrative, he reveals that Leo has recently been released from prison but has been involved in dubious activities involving corrupted law enforcement. Moments later, Gio is approached by two aggressive men, one of whom seems to have emerged from a nearby HVAC van. Concerned, he immediately calls Leo to warn him that the FBI is searching for him.
In his attempts to contribute to the family festivities—Gio is instructed to retrieve butter—he faces further obstacles. At the local bodega, he encounters a punk who causes issues and learns that the store's owner has been threatened over a property sale. Disheartened, Gio is unable to procure the butter.
Later, Gio drops by a bar looking for Leo, only to find Peeno outside, amidst other revelers boarding a limousine. After an exchange with Peeno where he highlights some questionable characters, Gio heads to Leo's apartment, but not finding him home, he notices the disruptive sound of loud rap music and a barking dog. Soon, Peeno arrives with some Puerto Rican associates hunting for Leo, who remains hidden from sight.
In a separate encounter, Gio visits his friend Tommy, who owns a bakery. Their conversation reveals Tommy's disdain for most people, including Gio, although his partner, Diane, shows kindness and assistance. Unexpectedly, when Tracey, another acquaintance, drops by after hours, she offers Gio a ride, leading to tension after Tommy's snide comments about Puerto Ricans.
Meanwhile, at a strip club, Gio meets Uncle Tony as Cousin Joey continues to stir trouble. Eventually, Gio arrives at a gathering at a family's home, greeted warmly with cautious optimism centered around his cake. Father Kelly narrates how Uncle Angelo hosted community events but now struggles to communicate following an incident that left him with speech difficulties, necessitating subtitles during conversations. Gio acknowledges a frail Uncle Carmine, who remains engrossed in his television show.
As the evening progresses, tension escalates when Uncle Ricardo, pushed by his frustration over Leo's secrecy, brandishes a gun. The circumstances shift even further as mysterious men arrive, changing the evening's dynamics; all the family’s women are attending a bachelorette party, creating a strange atmosphere. Despite pleasant dinner conversations and a toast for Gio's father, ominous hints surface as a close-up of the cake box is underscored by disquieting music.
Gio, realizing his allergy to chocolate, declines to eat. Soon, a shared knife to cut the cake is circulated, and the mood sours when diners begin experiencing life-threatening symptoms. Frantically piecing it together, Gio learns they’re all succumbing to effects from the cake. As he confronts Uncle Carmine about crass comments, Gio bolts from the scene toward Leo's, desperate to warn him.
Upon arrival at Leo's, he is confronted with a bloodied and frightened Leo attempting to fend off the well-armed Ricardo, resulting in an intense struggle. Unfortunately, Gio's efforts to save him prove futile. Devastated by the turn of events, Gio returns to the church, where Father Kelly, aware of the turmoil, provides comfort and thanks him for his tireless efforts. As Sofia emerges for an embrace, she remains tight-lipped about the night's events, choosing instead to offer support. After a moment of contemplation and a final lighting of the candle, Gio and the others depart, leaving him to grapple with the haunting legacy of his family's struggles.
