The unicorns' parents are older unicorns who set lethal traps to protect their foal after it is injured. They kill several members of the hunting party and later follow the survivors into the estate. They are docile toward Ridley, the pure-hearted maiden, but become violent when they realize their foal's horn has been removed, killing Dr. Bhatia. In the climax, they magically revive Elliot and their foal before leaving peacefully.

Shepard steals a vial of the unicorn's grated horn and snorts it, experiencing visions. He orders Dr. Bhatia to saw off the entire horn and later proposes breeding unicorns on a ranch to harvest their blood and horn for profit. He holds Ridley at arrow-point, trying to control the unicorns, but is ultimately stabbed with the horn and fatally kicked by a unicorn.

Ridley is identified as a 'pure-hearted maiden,' which causes the unicorns to be docile toward her. This trait is revealed through Shepard's visions after snorting the horn. Ridley's purity allows her to interact peacefully with the unicorns, which is crucial in the story's resolution when the parent unicorns become calm upon her arrival.

The hunting party falls into lethal traps set by the older unicorns, resulting in several deaths including Odell and Shaw. Later, Dr. Bhatia is killed by the unicorns after they discover their foal's horn has been removed. Belinda is disemboweled by a unicorn when hiding in the wine cellar. The unicorns kill multiple members of the hunting party as retribution for harming their foal.

After the unicorns revive Elliot and their foal, Griff returns with the police who arrest the Kintners. While being driven away, the unicorns ram the police car, causing it to swerve off the road as the occupants brace for impact. The film ends ambiguously, leaving it unclear whether the characters survive, emphasizing the ongoing threat and mystery surrounding the unicorns.