Irene Kelly, Michaela McManus's daughter Anna, Grace Van Dien is murdered by a restaurant cook named Neville Jeremy Holm. This tragedy sets off a relentless pursuit across multiple realities as Irene uses a universe-hopping machine to hunt down Neville's various versions. Across these parallel worlds, Irene pushes herself to the brink, driven by a need to confront the man responsible for Anna's death and to protect others from meeting the same fate.
In one of the alternate worlds, Irene encounters a teenage runaway named Mia, whom Neville intends to kill. Irene manages to drive Neville away, saving Mia, and for the moment she keeps Mia close, intending to guide her to safety. Yet Irene soon discovers Mia has taken her gun, setting off a new, urgent mission to locate the girl and ensure she stays out of Neville’s reach. Mia, hitch-hiking toward Neville’s hideout, hopes to end the threat herself, but Irene catches up and the two form a cautious truce to get rid of the common danger.
When Neville enters a gas station, a tense gunfight erupts among Neville, Irene, and the gas station clerk London Garcia. The clerk is wounded in the firefight, a stark reminder of the stakes. Irene urges Mia to jump into the universe-hopping machine, and after Irene shoots Neville, the pair lands in a new universe where the clerk remains alive. Irene explains that she has spent years tracking Neville’s variants, but the latest jump has drained the fuel core and left her with fewer options than before.
Seeking a new part to repair the machine, Irene tracks smugglers who might have what she needs. The smugglers demand Mia in exchange for the part, complicating an already high-stakes rescue. Billie, the head smuggler Taylor Misiak, steps in to defuse the tension, offering a refurbished component from a vehicle outside. Irene declines to pay their price in cash and fights to take back control, but the smugglers try to trap them in a large hopper. Irene and Mia manage to escape, and they kill one of the smugglers, securing the fuel core to continue their escape.
The pair lands in another universe where Irene reveals she is the sole version of herself who didn’t die after Neville killed Anna. She has sometimes used her abandoned home as a temporary base, a quiet sanctuary amid the chaos. While Mia sleeps, Irene makes her way to Neville’s home and learns that the Neville in this universe has murdered the new universe’s Mia. Shaken, Irene returns to Mia, who she has begun to care for, and a moral conflict unfolds: Irene wants to stop killing, but Mia’s anger pushes them toward new, perilous choices. This leads to a dangerous detour: they jump to a universe where Neville was imprisoned 15 years earlier, a place where Anna is alive.
Irene returns to a version of her own home where she sees herself and Anna seemingly happy. She steps out of the shadows and reveals herself to Anna, sharing a poignant farewell. Meanwhile, Mia shoots Neville as he is about to take the deceased Mia to his hideout, but Neville is able to knock Mia unconscious in the ensuing struggle.
Neville carries Mia and the dead Mia to his hideout, placing Mia into a barrel and dumping it into a lake. Irene arrives just in time to confront Neville and shoots him. Neville recognizes Irene as the mother of a victim and, in a fierce struggle, hurls her into the lake after she gets caught in a bear trap. As Irene sinks, Mia frees herself and defeats Neville, and Irene eventually surfaces, having broken free.
The two return to the house of the deceased Irene, where Irene sets the time machine ablaze. With the machine burning, Irene sits beside Mia, who rests her head on Irene’s shoulder as they watch the device burn away, choosing to end the cycle for now and face the uncertain future together.
