Dan Reilly, who owns a failing farm in rural Ireland, is being paid by a bio-genetics firm to assist in some experiments to make faster-growing cattle.

The firm sends Orla, a local veterinarian, to inspect the cows and ensure the experiment is running smoothly.

John also informs Dan of a caravan parked near his farm and reminds him that the experiment is supposed to be kept secret from the public.

Dan goes out and speaks to the inhabitants, Traveller Jamie and his girlfriend Mary, and tells them they must leave by morning.

In gratitude, Dan allows Jamie and Mary, who are on the run from her brothers who disapprove of her relationship with a Traveller, to stay on his farm.

She performs a necropsy on the calf and discovers that it was somehow pregnant with six foetuses, all of which are extremely deformed and have their skeletons growing outside their bodies.

John takes her body to the lab and finds foreign material inside a wound on her abdomen.

When Dan and Mary come outside to investigate, they find that John has killed almost every cow on the farm in search of the creature.