A chemistry student (Cheerleader Kait) is working on a new compound that can alter a microorganism’s DNA, enhancing their adaptation. When her partner (Ava Amira) arrives at the lab, she criticises Kait’s lack of safety measures, only to get shunned by Kait as she continues testing her new formula.

To their shock, the compound’s reaction with a microorganism accelerates, growing in size until every drop of the chemical has been absorbed. Kait and Ava witness the creation of a new species that has grown four inches in size. In an instant the organism attacks Kait, crawling into her mouth and invading her brain.

Ava tries to help Kait as she collapses to the ground in a series of convulsions, only to rise up possessing black lifeless eyes and bulging veins sprawling along her skin. Under the control of the organism, Kait pins Ava down and regurgitates her new master, allowing the organism to infect Ava’s mind and body.

With both students under its control, the organism uses its two human vessels to grow, commanding them to stimulate their bodies, sliding in and out of Ava and Kait’s internals during their sexual activity, incubating into a more powerful being.

Ava invites her friends Melody and Emma to come to her workplace, where they can sit together and share something to eat or drink. Whilst Melody is preoccupied, Emma arrives early, ordering herself a hot beverage and listening to Ava's gossip about her job. Rumours about the building's old history, the chef's shady activities, and a secret area known only as ?The Vault? entertain the two women. That is, until they notice the chef sneak into the cellar.

Following the chef's direction, Ava and Emma stumble into a stock room for the building, where they make a shocking discovery. They open a refrigerator door, revealing it to be a hidden entrance to a dark chamber. Filled with rattling chains and barely any light, Emma and Ava find an ancient Korean ornament mounted onto the wall.

The door suddenly slams shut, sealing the two women within the chamber. The Korean ornament begins to open, unleashing a slimy monstrous parasite into the room, causing the pair to panic in terror. It attacks Emma, leaping up her dress and burrowing inside of her pussy.

Ava watches in horror as her friend loses her mind, transforming into a corrupted version of her former self. The infected Emma restrains Ava, giving birth to a parasite into her mouth and laughing as Ava becomes infected too. Giving in to their insatiable lust, the two women must compose themselves if they wish to get what they truly want; for their friend Melody to join them...