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

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

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

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.

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