The planet's atmosphere is moderately toxic to humans, necessitating enclaves, or semi-encapsulated city-states, which influences Union's political outlook.

Azi are incubated in vitro in "womb-tanks", but citizen (or "CIT") babies can be cloned the same way, for example to replace a dead child.

The fundamental difference between azi and regular humans is that they are educated from birth via "tape", a computer-controlled combination of conditioning and biofeedback training.

This results in profound psychological differences; for example, CITs are much more capable of handling new and uncertain situations, while azi are able to concentrate better.

In addition to her research on azi, she runs Reseune (founded by her parents) with the assistance of Giraud and Denys Nye.

Her political enemies, headed by Mikhail Corain, prefer to focus on the existing stations and planets.

The Expansionists have held power since the foundation of Union, a situation fostered by "rejuv", which extends lifespans and staves off the effects of old age.

Justin has grown up with and is very close to Grant, an experimental azi created by Emory from the slightly modified geneset of another Special.

An earlier attempt with Estelle Bok, the inventor of the equation that led to faster-than-light travel, had failed miserably.

Emory's ultimate goal was to clone herself, with her successor reliving her life as closely as possible, down to her hormone levels and including two longtime bodyguard azi and companions, Florian and Catlin.

When Ari is nearly nine, the Centrists, in a bid for power, attempt to use a scandal involving Emory – the deliberate abandonment of a secret colony on the planet Gehenna.

The Reseune authorities have Ari legally recognized as Emory's clone, entitled to take possession of her predecessor's property, in order to block the release of potentially damaging information.

A major political crisis is precipitated by his death from old age, as well as the Paxers – a terrorist group – manipulating Jordan.

An attempt on Ari's life is barely foiled when Justin's just-in-time warning enables Florian and Catlin to deal with an unexpected would-be assassin.