While on a routine mission, the crew of the spacecraft “Alexander One” discovers a space-going fungus. Little do they know that the lifeform is really a sentient alien being on a mission—a mission that will affect everyone on board. Able to copy the form of any female creature it comes in contact with, it forms a mind link with the woman it copies—who is then able to feel everything the alien does! The extraterrestrial nourishes itself on the sexual energy of intercourse with the crew members, and quickly overpowers the ship. It’s up to the last surviving member of the crew, ANNE GALLO, to stop the alien!

When the ship arrives back on Earth, FBI Agents PRESTON AND FORREST are brought in to question Ms. Gallo…but Anne is not who she appears to be. The alien, now in Anne’s form, escapes the government compound—and the chase is on!

In hot pursuit, the two FBI agents must track down the shape-shifting alien. Unfortunately, it’s difficult to track down something that constantly changes shape. First the alien transforms into security guard KELLY CONNOR, and refuels itself by having sex with a man in a gas station bathroom. It then takes the form of the man’s girlfriend, MONIQUE, and escapes in her car. But Agents Preston and Forrest are right behind her in an exciting car chase across the Nevada desert.

In the next town, the alien runs into a nightclub and finally has a face-to-face encounter with the agents. Unfortunately, the creature manages to escape once more by taking the form of female agent Forrest.

Forrest, now linked with the alien’s thoughts and feelings, is able to find out the creature’s true mission and purpose on Earth. The alien is actually searching for her mate, and they are having their reunion at the Grand Canyon. Taking flight in a helicopter, the FBI agents chase the alien through the canyon. When the creature discovers how it is being tracked, it takes the shape of a tourist named EVE in order to break the psychic link to Forrest.

The final confrontation takes place in the underground caves at the base of the Grand Canyon. There, Preston and Forrest discover the alien’s lair—and battle both it and its mate!

In the struggle, the agents are overpowered, but the aliens do not kill them. They explain that they only want to return to their own planet, and that any deaths caused by Eve’s actions were unintended and deeply regretted. The male alien and the female alien come together in one last passionate encounter as human beings, then transform back into their original forms and fly off into outer space!

Agents Forrest and Preston are released, and decide their report will be submitted into the government agency that handles paranormal occurrences: the department of ‘The Sex Files.’