Earth is emerging into a field of radiation which allows the mind to perceive the world in incredible detail at levels from the microscopic upward.

It eventually becomes clear that SecBu is run by people who conquered the Screamies, and are bent on using their enhanced perceptions to gain and hold power.

The protagonist is tempted by the power brokers at SecBu, who need his skills, while a close friend sides with the aliens who are attempting to help mankind learn to live with the new perception.

Greg's twin brother Manuel had gone out on the first operational starship, the Nina, which was lost after sending messages about "a glowing ship" and "presences".

While visiting his fiancée Helen Forsythe and her father in rural Pennsylvania, Gregson follows up on an article in a local newspaper about a farmer who claimed that aliens tried to recruit him to help them.

The briefing consists of a show where an apparent drugged Valorian confesses to seeking the conquest of Earth, and to bringing the Screamie disease as a biological weapon.

Shortly afterward Gregson himself has his ultimate Screamie attack, and is sedated for removal to one of the many Isolation Institutes reserved for Screamers.

He endures months of psychic pain, apparent hallucinations, and terror, narrowly avoiding the typical fate of Screamers, who tend to commit suicide when their sedation wears off enough for them to reach a convenient high window.

Radcliff reveals to him the existence of a device which can suppress the Screamies over a small area, by blocking the effects of an unknown form of radiation.

Radcliff wants Gregson to help construct a super-suppressor on the space station Vega Jump-off, the departure point of the Nina, to cover the entire planet.

Discovering the head of the training institute asleep in a field of artificial rault he is able to zylph the man's true purposes from his mind.

Rescuing the occupant, a female, he drives to confront Madam Carnot, a conspirator who claims to be the oldest and most powerful zylpher on Earth.

The Valorian he rescued, who is called Andelia, tells him that his brother Manuel is alive, one of the few on the Nina who survived when the ship emerged into full rault.

Gregson, apparently free to leave the hideout, steals a craft and returns to Pennsylvania to find Helen, only to be captured by SecBu.

It is the supreme chance to decapitate the conspiracy, who plan to use their control over the super-suppressor to cement their power, threatening to turn it off if their demands are not met.

With them eliminated, the super-suppressor could be activated as planned, and with help from the Valorians humanity would be able to recover the lost perception, ready to deal with high levels of rault which must be coming.

In the opening sequence the attack on Gregson's flying craft involves both lasers and .50 caliber machine guns, which elicits the comment "Something old, something new" from Wellford.

The ability to travel into space is available to clandestine groups, suggesting great advances in propulsion over basic chemical rockets which require tons of fuel to place even modest payloads into orbit.

The Nina apparently also makes use of previously unknown propulsion systems, possibly the ion drives used in other contemporary novels, which allow acceleration to very high speeds if left running for long enough.