With Z-Lensman, the final novel in his post-E.E. Smith Lensmen trilogy, David A. Kyle turns his attention to the strangest of the three non-human Second Stage Lensmen: Nadreck the Palainian, whose Z-type species exists in a multidimensional state beyond the familiar three dimensions experienced by most of the galaxy's life forms. The constant shifting of their bodies through unfamiliar dimensions — together with the frightfully cold and poisonous atmosphere they breathe and their implacable emotional detachment — make the Palainians one of the more unsettling races known to Civilization. But, as events will soon demonstrate, they are also one of its most valuable assets.
In the process of training a new class of Z-type Lensmen cadets from the Palainian Z-Academy, Nadreck makes the unintentionally fateful decision to bring a religious leader from a Boskonian Spawn-influenced planet to be studied on Tellus before continuing on to Palain VII. On Tellus, Nadreck and the newly-promoted Galactic Patrol lieutenant Benson Cloudd become aware of a strange new problem affecting Civilized space. Machines throughout a wide swathe of the galaxy have begun to malfunction, and communicators, spaceships and computers are becoming increasingly unreliable. But in the process of searching for the source of this mechanical mayhem, Nadreck discovers something even more disturbing: remnants of the Eddorian Conspiracy are planning a new invasion, and their forces are gathering on multiple planes of existence!
Faced with mysteries and threats on multiple fronts, Nadreck, Cloudd and the android-bodied Lensman Lalla Kallatra must work together while at the same time scattering themselves across the stars, each in pursuit of their own piece of the puzzle. As the final confrontation approaches, all of the power wielded by Civilization — and all of the combined resourcefulness of its members, from Galactic Coordinator Kimball Kinnison personally leading the Patrol's Grand Fleet against an unprecedented weapon to the shade of Deuce O'Six defending the borders of the spirit world — must be brought to bear. But will it be enough? And will the threat that is closest to home be recognized in time?
All this and much more is revealed in Z-Lensman, the mesmerizing conclusion to Kyle's galaxies-spanning saga!