In this movie Genetic Engineers Clive and Elsa are hoping to successfully splice different animal DNA together to create hybrid animals for medical use. When they successfully create a male and female specimen they want to further their research by adding Human DNA to the mix. This is forbidden by the company that funds their research and are told to extract proteins from the specimens they've already successfully created.
Clive and Elsa decided to conduct their own experiments secretly. When their experiment looks to be successful, Elsa pushes Clive to let the hybrid continue to term though that it was not originally the plan. Elsa believes she may have killed the hybrid but discovers that it was actually inside some sort of cocoon type apparatus. The creature inside can survive underwater and so they put it in a tank of water.
They put the creature under anesthesia and examine it only to find that she is aging at an alarming rate. Clive expresses that he still believes the creature should be put down but Elsa points out that it would have a very short life cycle and they should let it go through its life cycle and complete their experiment. Elsa names the creature Dren after she realizes that she is capable of learning and at an alarming rate.
With spending more time with Dren Elsa and Clive forget to keep track of their original specimens. While these specimens were at an unveiling ceremony instead of mating they violently killed each other. It was later found out that the female specimen spontaneously changed to male. This information would have been important to know later on when they have problems with Dren.
When Dren grows into adolescence and they move her to Elsa's late mothers barn. Later Dren attacks Elsa cause a grudge between them and Elsa starts calling Dren the specimen again. Clive and Dren eventually get intimate as Dren is in her adult state and Elsa walks in on them.
Clive and Elsa have a heated argument in which Clive tells her that he knows she used her own DNA for the experiment instead of a Jane Doe. They go back to the barn to discover Dren had passed away and they bury her. Their boss comes to the barn to confront them about being suspected of using human DNA. Clive and Elsa come clean but express that Dren had already passed away.
Dren hadn't passed away but turned male much like their original specimens had. Dren appears and kills their boss and Clives brother, wounding Clive in the process. Elsa runs into the woods and Dren hunts her down and rapes her and then kills Clive when Elsa hesitates in the attempt to kill Dren.Elsa kills Dren in the end and at the end of the movie it is revealed that she is pregnant and talking to the head of the company she works for.