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.

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.

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.

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

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

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

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.

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