String Juno Temple as Diane is a young, blonde British teenager living in New York who suffers from chronic nosebleeds and a troubling, sudden transformation. One moment she peers into a mirror and the next she spirals into a monstrous change, collapsing unconscious as the eerie shift takes hold. The film’s opening threads a sense of unease through Diane’s fragile body and the inexplicable eruption of fear that follows.
Earlier on, [Riley Keough] as Jack crosses paths with Diane on the city streets when Diane is trying to borrow a cellphone to call her twin sister Karen. In a clothing store, Jack—a dark-haired, openly gay young woman—offers help and quickly shows a keen interest in Diane. A nosebleed returns, and Jack steps in again, guiding her through the crowded night. The two end up at a nightclub where Diane, feeling nauseated and bleeding, retreats to the restroom. The mood intensifies as she loses consciousness, and when she awakens, the pair share a fierce, intimate kiss with a group of friends on a couch in the lounge, signaling a powerful but volatile bond between them.
The following morning brings chaos: Jack is hit by a car, and Diane faces a stern confrontation with her aunt Linda, played by [Cara Seymour] as Aunt Linda, who grounds her. Diane’s defiance—“I’m not your mother”—highlights a shared sense of being misunderstood within their homes. Back with Jack, the actress portrayed by Riley Keough returns from the hospital to a tense, strained household where Jack’s own mother is neglectful, intensifying the sense of isolation each girl feels. Nevertheless, Diane continues to visit Jack, and their closeness deepens as Jack opens up about a sentimental cassette from her late brother, a fragile thread that both binds and unsettles them.
Aunt Linda’s provocations surface again when she hints that Diane might leave for school in France, prompting another argument between the two. The rift widens as Jack begins spending time with Tara, a coworker with whom she becomes entangled emotionally. [Kylie Minogue] as Tara enters the scene, bringing a new dynamic into Jack’s life. Diane, meanwhile, finds herself drawn to Chris, one of Jack’s circle of friends, portrayed by [Dane DeHaan] as Chris. The trio of friendships—Diane, Jack, and their companions—becomes the center of a slow-burning tension that tests their loyalties and desires. A game the girls play—with a stakes that could push someone to leave or stay—highlights the precarious balance of their evolving relationship. Jack’s win seals a moment of temporary harmony, but it is quickly undercut by the hard truth of their circumstances. When Chris discovers a troubling video on an adult site featuring Karen, Diane’s sister, sympathy for Karen racks Jack with guilt, and she inches toward reconciliation with Diane.
In the days that follow, the two women spend more time together, their romance growing yet shadowed by fear, longing, and the fear of losing one another. A dream where Diane morphs into a monster and devours her own heart becomes a chilling omen that lingers after Jack wakes to find Diane bleeding again on her side. As the countdown to Diane’s departure for France tightens, the bond between them becomes more fragile, strained by the looming distance and the fear of what might happen if Diane’s monstrous transformation ever fully takes hold.
A pivotal moment at a hotel swimming pool—where the lights go out in the locker room—frightens Jack, who seeks Diane for help with a Polaroid camera she had given her before the outage. The darkness separates them, and Diane searches for Jack by scanning through the camera’s images, encountering the monster once more. The two lean on each other for comfort, finding a sense of solace as they face the unknown together. When they finally reunite, their shared fear begins to ease, and they allow themselves a rare moment of tenderness, even as the relationship edges toward a breaking point.
On Diane’s final day before she heads off to school, the two girls confront the reality of separation and the complexities of their bond. Some weeks later, in Paris, Diane receives a gift from Jack—the cassette tape that has threaded through their shared memories—rekindling a bittersweet sense of nostalgia and reverie as she listens, reflecting on the strange and transformative journey they shared in New York.
- Diane [Juno Temple]-AT-FIRST-MENTIONED as Diane, a pale, luminous presence wrestling with a body that betrays her.
- Jack [Riley Keough]-AT-FIRST-MENTIONED as Jack, a bold, compassionate, and conflicted young woman who offers Diane both connection and danger.
- Tara [Kylie Minogue]-AT-FIRST-MENTIONED as Tara, a coworker whose presence introduces a fresh emotional thread into Jack’s orbit.
- Chris [Dane DeHaan]-AT-FIRST-MENTIONED as Chris, a friend whose involvement intensifies the web of relationships and consequences.
- Aunt Linda [Cara Seymour]-AT-FIRST-MENTIONED as Aunt Linda, a stern figure who pushes Diane toward boundaries and independence.
- Jack's Mom [Haviland Morris]-AT-FIRST-MENTIONED as Jack's Mom, a neglectful parent whose absence worsens the girls’ sense of isolation.
This tale unfolds with a clinical, observant eye, never losing sight of the emotional core: two young women seeking belonging, navigating danger and desire, and confronting a mysterious, disquieting force that threatens to redefine who they are—both to themselves and to each other.
