Will drives with his girlfriend Kira to the Hollywood Hills home of his ex-wife Eden, who is hosting a dinner party with her new husband David. The gathering includes their friends and a few others, all bound by a recent history of grief following the death of their young son Ty. Will and Eden have a tense history, having divorced after Ty’s death, and Eden’s life now centers around the new household she shares with David, who met her at a grief support group in Mexico. The guests include Tommy and his boyfriend Miguel, as well as friends Ben, Claire, and Gina, with Gina mentioning that her boyfriend Choi is running late. Eden also introduces Sadie, a girl she and David met in Mexico who is staying with them, adding an unsettled undercurrent to the evening.
As the night unfolds, Will moves through the home and revisits memories, including scenes that reveal Eden’s earlier struggle with despair. A moment in the kitchen when Eden lashes out at Ben after a joke about managing pain exposes a fragility beneath the party’s polished surface. The atmosphere remains uneasy, with Eden and David’s social circle trying to appear welcoming while hinting at something more elusive and alarming. Their friend Pruitt arrives, and David locks the front door, citing a recent home invasion in the area. Will steps outside for firewood and, through Eden’s bedroom window, sees Eden stashing a bottle that Will later learns contains phenobarbital, a detail that deepens his sense that something hidden is at play.
David and Eden share the story of The Invitation, a group they joined that uses a ritual-like approach to grief, framing their experiences as a path to release and healing. They screen a video featuring Dr. Joseph, the group’s leader, who offers comfort to a dying woman in her final moments. The guests participate in a playful yet tense game called “I Want,” where Sadie kisses Gina, Eden kisses Ben, and Pruitt speaks of killing his wife and serving time in prison. The mood shifts as Will questions the group’s philosophy and their insistence on an almost ceremonial sense of belonging. Claire is unsettled and considers leaving, but David urges her to stay, while Will’s suspicions grow. He notices Pruitt taking Claire away for a private conversation, and David confronts Will about his suspicions, attempting to reassure him.
After dinner, Will observes Sadie through a cracked door as she makes odd faces into a mirror and then follows him outside, offering an unsettling, provocative moment that he rejects. He discusses the party’s odd, dangerous energy with Tommy, who tries to normalize Will’s discomfort by suggesting that feeling strange is natural when stepping into a space with a heavy past. Will eventually connects with a voicemail from Choi, who indicates he was at Eden and David’s doorstep, a clue that raises Will’s paranoia about what is really happening in this house. Choi’s arrival later that night is a reminder that there may be more to the gathering than everyone is willing to admit. The other guests assume Will’s grief over Ty is coloring his judgment, while the house itself seems to press in from all sides.
David lights a red lantern in the garden, a symbolic touch that intensifies the sense of ritual and foreboding. Will discovers a laptop with a foreboding message from Dr. Joseph, and the evening’s toast attempt is interrupted when Will sensibly smashes the glasses, fearing they might be poisoned. The tension erupts as Sadie attacks Will, who inadvertently knocks her unconscious. Gina, who had sipped her drink earlier, collapses and dies, plunging the party into chaos. The attack escalates as David, Pruitt, and a recovering Sadie assault the guests, killing Miguel, Choi, and Ben. Will, Kira, and Tommy flee and hide within the house, their fear mounting as Will overhears David explaining that they have been chosen and that finishing what they started is the only way to be free of their pain.
In a desperate scramble for safety, Will takes a fireplace poker from a dying Sadie and fights back as Pruitt finds and attacks him and Kira; Kira defends themselves, and Pruitt is killed with a wine bottle. Eden shoots Will, wounding him, and then shoots herself in the stomach with a heavy sense of remorse. David stalks the survivors with a knife, but Tommy disarms and fatally stabs him. Eden, apologetic, asks Will to help her outside, and the trio—Will, Kira, and Tommy—carry the wounded Eden into the garden as sirens, screams, and helicopters rise in the distance. They look around to see more than a dozen nearby homes lit with red lanterns, revealing that other members have launched similar acts, and the night ends with a chorus of chaos echoing through the neighborhood. The film leaves the sense that the grief they sought to escape has spread, and the ritual of The Invitation has claimed many lives, reshaping the community in a single, chilling night.
