The books are set in a not-too-distant future where humans have colonized a number of other planets across the galaxy, thanks in part to technological assistance from an ancient alien race, the Ildirans.

The series chronicles the universe-spanning war that erupts when humans inadvertently ignite the fury of a hidden empire of elemental aliens known as the hydrogues.

Centuries before, several generation ships had set out from Earth to find new worlds; one of these had encountered the Ildirans, an ancient alien race who shared their stardrive technology (which allows faster-than-light travel) and led the humans to habitable planets.

Basil looks to expand the human empire further through the discovery of alien technology from the extinct Klikiss race that will allow scientists to create a new star from a gas giant, turning cold moons into planets ripe for colonization.

The Roamers are clans of industrious humans living a clandestine existence in the fringes of space, managing a profitable economy centered on the sale of the valuable stardrive fuel ekti and other commodities.

Their brutal retaliation and forced cessation of ekti collection threaten to cripple both the human and Ildiran civilizations, and serve as an effective declaration of war.

Instead readers obtain a powerful futuristic epic that contains a robust stand-alone story line yet provides a puissant cliffhanger that will keep the audience wanting to continue non-stop.

As the novel begins, the Hansa's test of a recently discovered ancient Klikiss technology that can convert gas giant planets into suns is a success.

Confined in crystalline globe ships, the hydrogues retaliate by systematically destroying several Roamer skymines, floating factories which harvest the hydrogen used to produce the vital stardrive fuel ekti from the atmosphere of gas giants.

The humans and Ildirans mount a defense to protect their interests, but the virtually indestructible hydrogue ships and their lightning and ice weapons seem an unconquerable enemy.

Calling Anderson's characters "well-drawn," Publishers Weekly wrote that the author "weaves action, romance and science with a rousing plot reflecting the classic SF of Clarke and Herbert and the glossy cinematic influence of Lucas and Spielberg.

Though a heartbroken Jora'h believes she is dead, Nira is secretly a captive being used in the clandestine breeding scheme of Mage-Imperator Cyroc'h to create an Ildiran capable of communicating with the hydrogues.

Hansa Chairman Basil Wenceslas (and his figurehead King Peter) attempts to unify all branches of the human race to stand together against the threat, even if they must resort to deception and oppression to do so.

Speaker Cesca Peroni, leader of the Roamers, finds herself stranded on a small icy outpost where miners have uncovered a hibernating army of Klikiss robots.

Publishers Weekly wrote that the "fabulous fifth volume ... combines glitzy space-opera flash with witty, character-driven action on a cosmic scale," and again complimented Anderson's ability to manage multiple plotlines and a large cast of characters.

Ancient verdani thorny tree battleships arrive after a long journey across the universe to aid Theroc, while the Roamers' plan to seed aquatic planets with wentals to rejuvenate the elemental race comes to fruition.

Publishers Weekly noted that while the series "has been compared to some of the genre's grandest epics with good reason," Metal Swarm itself "fails to satisfy on its own merits" and "much of the action-packed conflict remains relatively predictable.

[9] He commented that by the sixth installment "one would hope for a kind of summing-up or accelerando or intensification of pitch" but felt that "the initial states of the protagonists remain essentially static.

King Peter and Queen Estarra, having escaped Earth and Basil's plot to kill them and their unborn child, have fled to Theroc and declared a new Confederation.

At the end of his rope, Hansa Chairman Basil Wenceslas has alienated all of the other factions in the Spiral Arm in his increasingly myopic and destructive struggle to reconsolidate the power he once held over the human race.

The Ildirans help the inhabitants of the Caillié settle the planet Theroc and rescue most of the remaining human ships, then send an envoy to Earth seeking an alliance.

Instead readers obtain a powerful futuristic epic that contains a robust stand-alone story line yet provides a puissant cliffhanger that will keep the audience wanting to continue non-stop.