Hideous!

Martin, a questionable water sanitation worker, finds a fleshy organism in a water treatment tank. He contacts Belinda Yost at IMSI to report the strange specimen. Yost rushes to the scene, eager to turn it into a sale.

Yost speaks with Lazar and secures a deal: a check for $650,000 and a commitment to spend at least $200,000 per year for 10 years. She pays off Martin and arranges a meeting at IMSI's cold storage level where Lazar will inspect the specimen. The sale is set in motion.

On the way home, Lazar is ambushed by Sheila, who wears nothing but a miniskirt and a gorilla mask. She handcuffs Lazar to a tree and steals the specimen. She delivers it to Lorca's castle, where he places the jar in preserving liquid inside his study among other oddities.

Lorca places the new specimen in a jar on a shelf with three other grotesque oddities. The revived creature reanimates the other three, resulting in a quartet of monstrous beings with bizarre appearances. The chamber houses a blob, a brutish hairless ape, an emaciated skeletal figure, and a spiny-headed entity.

Lazar, Yost, and Elvina seek PI Leonard Kantor to track down the thief. After pressure, Elvina admits she informed Lorca about the sale. They decide to confront Lorca at his castle.

The trio arrives at Lorca's castle and learns Lorca plans to impress Lazar with his collection. They discover the four jars are broken and the specimens gone, with tracks leading to a vent shaft. Lorca locks down the castle as chaos erupts.

With the humans locked away, a tapping on the wall signals that the specimens are alive. Through the wall, the four communicate with the rescuers by answering yes/no questions, guiding them to pry open the locked closet door. The four grotesque beings are finally revealed.

When Yost goes to gather the specimens, she is knocked down by the skeletal creature with its spine-like hair. The hairless ape attacks Sheila, and the blob grabs the human's gun, turning the scene chaotic. The group barricades themselves in a bedroom to hold off the monsters.

Elvina is sleeping on the bed as the hairless ape begins breast-feeding under the blanket. She wakes in panic, runs from the room, trips, and plummets over a balcony railing to her death. The remaining humans brace for the mounting danger.

The remaining five descend below in search of the creatures. Lorca and Lazar attempt to lure the monsters, but the beings scatter. A sword fight erupts between Lorca and Lazar, and Yost triggers a boobytrap while escaping, leaving her impaled.

The duel threads toward an acid bath trap; the hairless ape triggers the mechanism. Lorca and Lazar fall into the acid and dissolve, ending their bid for control of the specimens. The room fills with danger as the remaining creatures roam.

Sheila uses the security override to lure the specimens onto a carpet and sweeps them into the open acid bath. She and Kantor escape in Kantor's car, unaware of the bloody tracks and the creatures seen through the trunk’s keyhole as they drive away.