The story kicks off with Elliot Kintner (Paul Rudd) and his teenage daughter Ridley (Jenna Ortega) heading to the remote estate of Elliot’s boss, Odell Leopold (Richard E. Grant). While Elliot deals with his relentless allergies, Ridley is visibly disinterested and emotionally checked out.

A Shocking Encounter on the Road

During their drive, Elliot unintentionally hits a young unicorn. As they stop to assess the situation, Ridley touches the otherworldly creature, triggering a vivid, celestial vision that immerses her in a mysterious cosmic landscape. Her trance is shattered when Elliot violently kills the unicorn with a tire iron in an effort to end its suffering.

Welcome to the Leopolds’ Estate

Upon arrival, the pair meet Odell—gravely ill—his wife Belinda (Téa Leoni), and their son Shepard (Will Poulter). Elliot’s visit is work-related, but Ridley remains haunted by their recent experience. Suddenly, their van begins to shake. Rushing outside, everyone watches in horror as the presumed-dead unicorn springs to life in a panic. The chaos ends when Shaw (Jessica Hynes), the Leopolds’ unshaken assistant, executes it with a precise gunshot.

Unicorn Blood Reveals Strange Powers

They examine the unicorn’s remains and make a stunning discovery: both Ridley and Elliot, having touched its blood, are healed—Ridley’s acne vanishes, and Elliot’s allergies are gone. The Leopolds quickly assemble a research team led by Dr. Song (Steve Park) and Dr. Bhatia (Sunita Mani) to unlock the unicorn’s medical potential.

Odell sees the unicorn’s blood and horn as the key to curing his illness. Meanwhile, Ridley grows more uneasy with each experiment, increasingly alarmed by the ethical gray area they’ve entered.

Greed and Transformation

Odell undergoes treatment and miraculously recovers. Shepard, on the other hand, snorts powdered unicorn horn, experiencing bizarre mental shifts and a mystical connection to the creature—echoing Ridley’s earlier vision.

As the lab experiments intensify, a strange phenomenon appears in the night sky—a shimmering aurora. This marks the arrival of a second unicorn, much larger and darker. It charges into the lab, kills Dr. Song in a gory display, and causes mass panic. One guard is trampled to death, while Elliot scrambles to protect Ridley. The shadowy unicorn finds her—but instead of attacking, it emits a sorrowful cry. Before Ridley can respond, Shaw’s team storms in, opening fire and forcing it to retreat.

Hunting the Unnatural

Odell sends his men into the woods to track the creature. Simultaneously, Shepard orders the horn severed from the baby unicorn’s corpse, severing Ridley’s psychic link. Realizing the unicorn may still be saved, Ridley texts Elliot, warning that they’re stepping into a deadly trap.

Her warning proves true. The dark unicorn returns—this time with its mate. The two violently wipe out Odell’s gunmen. Shaw is dragged off, presumably killed. Odell, inflated by his supposed immortality, walks right up to the beast. It answers by driving its horn through his skull from chin to cranium.

An Attempt at Redemption Fails

With Odell gone, the survivors seek a way out. Griff (Anthony Carrigan), the head of security, heads for help. Ridley suggests they return the baby unicorn’s body to make peace. Dr. Bhatia agrees, but the hornless corpse enrages the parents. The unicorns rip her apart.

As the estate is overrun, Belinda is fatally gored. Shepard, with a flaming arrow ready to explode a nearby gas tank, considers mercy—but hesitates. The unicorn finishes Belinda off instead.

A Final Stand and a Supernatural Resurrection

Having seen enough horror, Elliot sides with Ridley and takes it upon himself to return the horn. Ridley attempts to escape but is intercepted by Shepard, now fully convinced the unicorns only attack the wicked. He plans to use Ridley as bait to prove his theory.

Just in time, Elliot arrives and stabs Shepard with the unicorn’s horn. In a final gasp, Shepard wounds Elliot, but the female unicorn delivers the killing blow—its glowing horn smashing through Shepard’s head.

As Elliot lays dying in Ridley’s arms, the unicorns approach. Instead of finishing them, they restore Elliot and their own child, using their mystic energy to resurrect both. Elliot experiences the same celestial vision that Ridley had, bathed in starry wonder.

A Haunting Ending

With the unicorns now glowing white in peace, they vanish into the forest. But the peace is shattered when Griff returns with the police. Seeing the carnage, they arrest Elliot and Ridley, suspecting them of mass murder.

As they’re driven away in a squad car, Elliot shares the vision with Ridley. Then, through the window, they see the unicorns galloping alongside the vehicle. In the final, jarring twist, the unicorns smash into the police cars—signaling that their tale is far from over.