After escaping on a small plane, the Brute attacks the two crew members while in flight. Tossing both men to their deaths, the plane inevitably crashes over rural Minnesota.

The crash site is quickly discovered by Dr. Karlheinz Speer and his assistant Eric. They take the unconscious Brute back to their laboratory and implant a mind control device in his brain.

Meanwhile, Chief Frazier informs Dr. Turner that he suspects that the Brute may have hidden aboard a plane that has recently crashed. Dr. Turner quickly sets out for the crash site.

Upon awakening from the surgery, Dr. Speer orders the Brute to kill Eric, who has outlived his usefulness. The Brute is powerless to resist and quickly dispatches Eric.

Dr. Speer now sends the Brute out to kidnap the 3 board members of the United States Academy of Science, who voted to expel Dr. Speer for performing experiments upon kidnapped human subjects. Dr. Speer's dream is to create a race of Reptile Men, capable of living underwater. The Brute succeeds in kidnapping all 3 board members, who Dr. Speer quickly turns into Reptile Men.

Dr. Turner arrives at the crash site and finds her way to Dr. Speer's laboratory. The Doctor quickly orders the Brute to kill her when she spots him. Recognizing her as his friend, the Brute is unable to carry out the order. He turns on Dr. Speer who releases his Reptile Men to kill the Brute. The Brute makes quick work of the Reptile Men and kills Dr. Speer. An explosion devastates the laboratory as Dr. Turner barely escapes with her life. Thinking the Brute dead, she leaves the area. Unbeknownst to her, the Brute still lives.