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

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

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

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.

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.

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.

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

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.

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.

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.

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

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

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

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.

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

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

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

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

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

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

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

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.

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.