A cop, Hal Corman, makes a routine traffic stop. A young man grabs the metallic disk and the cop becomes unconscious. The man is in the hospital suffering from the nightmare that he saw an alien. David Vincent comes in to investigate. Another cop, Lt. Greg Lucather, however, is suspicious of Vincent and drives him out.
Vincent tells his case to his wife. Vincent tells Greg to have protection on Hal. Later though we learn that Hal died. Vincent knows that he was murdered by the aliens. In the parking alley, an alien posing as a cop tries to kill Vincent. Lt. Lucather makes the save but is bewildered when the man he shoots turns to red dust.
Lucather gives the authorities a fake account of what happens. Lucather and Vincent talk about what's really going on and decide to work together. Tracing down a lead on the traffic stop that Hal made, Vincent and Lucather meet a scientist, Ms. Lowell, the owner of the station wagon that the young alien was in. She tells them a tale about the mysterious disappearance of a scientists named Dr. Lanier. She gives them a tour of her lab and tells them of a secret experiment that Laneer was working to create life. After Vincent, Lucather and Lowell leave, we see that one of the cops is under the control of the aliens. The whole lab is under the control of the aliens. Vincent tells Ms. Lowell about the alien invasion. Lucather runs down a lead of his own but Vincent thinks it's a trap because Corman's wife wasn't cooperative with Lucather earlier. When Vincent tries to reach Mrs. Corman, he learns that she's left town so Lucather is walking into a trap.
Vincent finds the station but is caught by an alien. He meets up with Lucather and tells him that the station is being used for regeneration and making human counterparts for aliens. Vincent makes a daring escape by flying through a window. Vincent, Lucather and Miss Lowell drive down to the sealab. Vincent now tells Lucather what happened. Laneer was sick and possibly regenerated by the aliens. However, for one reason the regeneration didn't work. Lucather and Vincent see that Laneer's body is held in a tank being regenerated by the aliens.
The aliens fight Vincent and Lucather. Laneer's body in the tank, however, disintegrates. Lowell has a breakdown and is put in the hospital. Vincent and Lucather discuss what happened and decide to have coffee.