A middle-aged Reza (Jonny Lee Miller) lives in a secluded shuttle settlement on Mars alongside his wife Ilsa (Sofia Boutella) and their curious nine-year-old daughter Remmy (Brooklynn Prince). Their little world, predominantly self-sufficient with a poultry farm and a greenhouse garden, feels safe yet stifling. Remmy longs to explore the vastness beyond their home, but her mother forbids her from doing so, further fueling the girl's curiosity.
One fateful morning, a disturbing word – "LEAVE" – is found scrawled on their kitchen window, sending chills down the family's spine. Tension simmer between Reza and Ilsa, suggesting they know more about this ominous warning than they let on. Before revelations unfold, three khaki-clad rangers invade their peace, and in a desperate act of protection, Reza confronts them. He bravely departs to finish what he started but fails to return.
As days trickle past, Ilsa and Remmy spiral into despair, anxiously awaiting Reza’s return. Their situation takes a turn when a mysterious ranger named Jerry (Ismael Cruz Córdova) breaks into their home, violently taking them hostage. Jerry claims that this is his family’s home and accuses Reza and Ilsa of being responsible for the deaths of his parents.
In a gripping confession, Ilsa explains that his mother was already deceased when they arrived and that they crash-landed on this planet from Earth. A tragic series of events transpired, forcing her to defend herself when faced with Jerry’s father during her pregnancy, leading to the violent history that now binds their lives.
Jerry's intentions remain ambiguous as he tries to congregate with the family, demanding thirty days to prove his worth to Ilsa and Remmy. As time unfolds, an unsettling bond grows between Jerry and Ilsa, but once the thirty-day mark hits, it ends in chaos. Ilsa attempts to end Jerry's threat but tragically learns that the gun's magazine, which Jerry had manipulated, is empty. An ensuing struggle leads to her death, leaving Remmy, who remains bitter and withdrawn, grappling with grief. She finds solace with "Steve," a quirky robot companion scavenged from storage.
Years slide by, with Remmy now a young woman, enveloped in silent resentment towards Jerry. He manipulates her into believing their settlement holds all she needs while ominously claiming that the outside world is barren and perilous. Yet, the call of the unknown tugs at her heart, increasingly challenging her resolve against living with her parents' murderer.
Jerry's tragic desire to breed with Remmy complicates matters further, revealing his terrifying intent to preserve his lineage at any cost. In a chilling moment of control, he destroys all oxygen masks to keep her trapped. Yet, Remmy's spirit rebels; she hides a mask beneath her bed. When Jerry discovers her secret, he reacts violently, attempting to assault her. But in an unexpected twist, her beloved robot, Steve, intervenes, saving her from the brink.
Together, Remmy reclaims her freedom by eliminating Jerry once and for all. With newfound resolve, she manages to rebuild Steve, crafting an oxygen mask that symbolizes her rebirth. As she prepares to leave the oppressive settlement behind, she entrusts Steve with its care. Remmy steps into the unknown, venturing through the hidden chamber to explore a world teeming with possibility, ready to embrace whatever fate awaits her amidst the stars.
