Species 2 Commandant Patrick Ross leads an crewed mission from Mars. The astronauts discovered soil samples that were contaminated with an alien-based substance. This substance thaws inside their capsule and contaminates it, resulting in a seven-minute contact gap between the mission’s control. With seemingly no subsequent negative effects, the three astronauts return to Earth to a public celebration. However, Dr. Cromwell, an ex-scientist who is in a mental facility, reacts with panic to the astronauts’ return. Dr. Laura Baker, who has developed a clone known as Sil and has suppressed her alien DNA to make her more docile. Her team is conducting experiments on Eve and hopes to discover ways to fight the alien race should it ever return to Earth. Each experiment fails because Eve’s biological makeup changes.
The members of the team are instructed to avoid all sexual activities for ten consecutive days upon their return. Patrick disregards this advice and has a threesome with two sisters Marcy and Lucy after a fundraising. The tentacles begin to grow as he has sex. Lucy observes the change while she is touching his body and is horrified at his appearance, whereupon she tries to free herself from his clutches. He refuses to listen and continues to build up to a climax. The hyper-fertile alien sperm in Marcy and Lucy makes them both experience accelerated pregnancies, culminating in the moment that Patrick’s half-alien babies explode violently from their stomachs. The rapidly growing sons of Patrick are kept from view by Patrick, Senator Judson Ros. Each time Patrick has sex, Eve experiences excitement. The following day, Patrick tells his father that he doesn’t remember what happened the night before. Senator Ross declares that he’s aware of Patrick’s behavior and tells him to focus on his political goals. Species 2 HD
Dr. Orinsky is one of the NASA researchers who examined Patrick. He discovers something wrong with his blood sample and desperately attempts to contact Cromwell. But, Orinsky is ambushed and removed from his body by a substance derived from Patrick’s blood. Laura discovers that Orinsky’s DNA differs from Eve’s. This makes her an unlikely suspect for the murder. To stop the threat the Colonel Burgess, her military supervisor brings Laura back together with Press Lennox. Press and Laura are able to locate Cromwell, Orinsky’s former professor. They learn that Cromwell discovered that an alien race had destroyed Mars in ancient time. Cromwell was worried that alien DNA could remain on Mars and infect future visitors to Mars. He advised the government not to end the mission but was ultimately committed to an institution to discredit him. Cromwell then states that the night Orinsky attempted to contact Cromwell was to prove that he was correct all along.
Press and Laura confirm Mars astronauts to be the prime suspects. They are unable to locate Patrick who is missing, they search for the other astronauts, Anne Sampas and Dennis Gamble. They arrive way too late for Anne to have sex with her husband. This leads to her being immunized with hybrid offspring. A tentacle-like creature bursts from the abdomen of Anne and kills her husband. Press and Laura manage to kill the monster. Another team of agents arrives in time to locate Dennis and check whether he’s in good health. Laura finds out that Anne has a hybrid DNA that is not compatible with Orinsky’s. Patrick is the murderer. While she is there, Patrick has sex with his partner, which results in her death due to the birth of a hybrid son, named Portus. In a state of shock at the fact that she has died, Patrick attempts suicide by shotgun but the alien DNA regenerates his head and restores him back to life and temporarily killing the human part of him, accompanied by the drive to mate with as many women as possible. Dennis observes this and reveals to Press and Laura the details of what he witnessed, remembering what happened in the capsule, and joining them in their mission. Patrick starts to immunize as many women as possible and hides his victims from view, possibly having up to 20 children on the father’s land.
Laura is ordered to activate Eve’s alien DNA in order that she is able to psychically follow Patrick however this can make her unstable and intensifies her alien instincts. After Darlene is raped by Patrick, Dennis and Press are able to take Patrick to custody. They then find out that Eve is alive and they take him to the laboratory despite their suspicions. While Patrick is detained, Eve shows signs of being in heat. Patrick demands Laura to open her cell. She almost kills her when Laura refuses. Press and Dennis are able to drive him away using an energizing gas weapon. Burgess confronts Ross and provides him with the undisputed evidence of Patrick’s condition. He demands his help in the pursuit of Patrick. Ross suspects Patrick is going to be killed, and then he claims that he’s in the area. Patrick’s human side briefly resurfaces and he tearfully embraces his father The alien DNA then quickly re-emerges and eliminates the Senator. Ross’s death completely destroys Patrick’s humanity. He aids his hybrid children in cocooning so that they can soon start mating and prepare to wipe humanity out. Species 2 HD
Laura is back in the lab and discovers that Dennis isn’t afflicted. Dennis is a carrier sickle cell disease. The species is deficient in immunity against human genetic diseases. They are planning to utilize this weakness to benefit themselves However, Eve escapes from her prison to find Patrick. Press, Laura and Dennis follow her, as well as Burgess as well as the military. They kill Patrick’s offspring at the shed. Eve and Patrick transform into alien-like forms and begin to mat. Dennis and Press intervene to stop the mating. Eve is able to get away from Patrick’s grasp, while Patrick transforms into an alien-like form and is able to attack Eve by slashing his tongue. Patrick attempts to attack the group, but Press strikes male aliens in the back with a pitchfork coated in Dennis’ blood, causing the alien to break apart and die.
The military takes Press, Laura and the wounded Dennis away. The apparent dead body of Eve is transported to an ambulance. However, shortly thereafter her uterus starts swelling rapidly. This is a sign of her survival , as well as the immunization administered by Patrick. Portus watches. The screen cuts to black as Eve’s uterus bursts, and her screaming can be heard. This is the beginning of the third movie.