An architect's close encounter with a spaceship leads him to investigate a small town's hydroelectric plant.

David Vincent meets with an eminent astrophysicist who has proof that aliens are invading the planet.

With the assistance of Vicki, a nightclub stripper, Vincent continues his search for an alien spacecraft.

Vincent is called on by a renowned electronics expert who fears he may soon be abducted by alien invaders.

Vincent's search for aliens lead him to an underwater sea lab.

A dying telephone lineman's fantastic story leads Vincent to investigate a huge industrial complex owned by a famous war hero.

Vincent travels to a small town to check a possible link between the aliens and an attack of carnivorous insects.

Vincent is called upon to help avert possible alien infiltration at a government nuclear test site.

While investigating the theft of a mysterious cylinder from the site of a plane crash, Vincent is captured and suspected of being an alien.

The aliens take David Vincent up into their spaceship and then attempt to prove they have nothing but peaceful intentions by showing him what they've done to a desert valley. But all is not what it seems.

Vincent discovers that a school is being used by the aliens as an indoctrination center.

Vincent discovers a mysterious computer tape that could offer proof of the alien invasion.

Vincent is contacted by a meterologist to help investigate the suspicious nature of a hurricane along the Eastern U.S. coast.

The invaders and Vincent race to capture a wounded alien whose touch brings on freezing death.

Vincent helps a security official investigate the deaths of two lunar astronauts in a strange red fog.

David's brother, who also thinks he is crazy, is kidnapped by the aliens who intend to destroy the oxygen in our planet's air.

The invaders frame Vincent for the death of an owner of an electronics plant who had made discoveries about the aliens.

Vincent attempts to thwart the alien infiltration of a Air Defense Command Unit.

Vincent battles, then destroys an alien guard and captures one of their spacecraft.

A hysterical hotel manager tells Vincent aliens are taking over his hotel.

After an alien is captured in a small town, Vincent warns the townspeople, who assume their captive is a madman.

Despite Vincent's warnings, a nurse tries to help an injured alien survivor of a saucer crash.

A man seek's Vincent's aid after he is arrested and put on trial for murder after the incineration death of an alien.

Vincent is horrified to learn the invaders are using strange seed spores that after cultivated will develop into full-grown aliens.

While investigating the Invaders susceptibility to minor human ailments, Vincent unknowingly is taken aboard an alien spacecraft.

In Part I of this two-part episode, Vincent uncovers a diabolical alien plot to destroy all of the world's leaders.

In the conclusion of a two-part episode, Vincent must defuse an experimental rocket that if ignited will destroy all heads of state gathered at a world summit meeting.

David exposes an alien disguised as a prophet who capitalizes on his ability to glow red as a tool to deceive people into thinking that his ""gift"" is from God.

When David Vincent brings an injured alien into the doctor for treatment, the patient's x-rays reveal odd results. While David works to alert the authorities, the aliens conspire to destroy both evidence and witnesses.

A Russian ambassador summons David Vincent after he finds that a burglar caught inside the embassy is an alien.

David Vincent is kidnapped in a sneak attack on his new found alien-fighting allies, and he must try to escape an alien installation with a human psychologist.

David Vincent and Bob Torin capture an alien leader, whom they hope to show to the authorities as proof; however, the leader's alien comrades foil David's efforts.

David Vincent is called in to aid a huge magazine publishing company that has been experiencing disruptive behavior in its company heads, and David believes that the aliens are behind the troubles.

An old college buddy sends David Vincent an urgent message, without any further details other than that it is important. When David arrives, Ted has been brain washed so that he can no longer remember why in the world he'd wanted to see his friend. It soon becomes obvious that the aliens are using mind control of some sort.

David deceives the aliens that he is willing to work with them for a fee, all the while with a plan of attack in mind.

Julian Reed calls upon David Vincent to help him expose aliens who have infiltrated The Slaten Research Center. By the time David arrives at the scene, Julian's having hallucinations. Is Julian truly a lunatic, or are the aliens behind his mental lapse?

David Vincent joins forces with the mob when the aliens inadvertently take their illegal shipment of drugs.

David Vincent arranges a meeting between the alien leaders and an Air Force General, who secretly plans to drop a bomb on the alien leaders despite the fact that many innocent people will die in the process.

Racist issues arise between David Vincent and the Baxters, a black couple, when David produces evidence that another African American in line for an important position with the space program is actually an alien.

In a small New Mexico town, a provincial teenage girl witnesses an alien’s incineration and believes it to be a sign from God.

A pair of aliens who want to return to their home planet and make a political argument against the invasion of Earth ask David Vincent to help them elude an intensive police manhunt.

The aliens’ experiments with artificial human emotions go awry when one of their subjects, prone to homicidal rages, defects to David Vincent’s side.

David Vincent and Edgar Scoville attempt to warn a senator that a governmental official is an alien, while Andy Hatcher tries to prove otherwise.