On the distant moon of Ylum, an enigmatic man is plagued by nightmares. He is forced to dream of the past. He dreams of real-life butchers and tyrants, and what they have done. And then he finds them, and kills them. The year is 2841, and this man is Nexus, a godlike figure who acts as judge, jury, and executioner for the vile criminals who appear in his dreams. He claims to kill in self-defense, but why? Where do the visions come from, and where did he get his powers? Though a hero to many, does he have any real moral code? These are but some of the questions that reporter Sundra Peale hopes to have answered.

Ylum shakes with the Merk's rage! Nexus sent Gucci-trained Quatro assassins Kreed and Sinclair to do his work of killing mass-murderers, but since then they've butchered over three thousand people in pursuit of two hundred! Now afflicted with a Quatro disease that will not allow them to stop, the pair are demolishing Mars and Nexus must intervene before the planet's authorities go nuclear. Sundra joins an intrigue in the Crystal Ballroom's library, Nexus infiltrates a Chernenko prison, and the "young" chairperson of the Central Committee - Konstantin - escapes captivity with Clausius the Slaver. Meanwhile, General Loomis' daughters plot their revenge!

The Merk is restless, dissatisfied with Nexus' performance as champion and executioner since the massacre on Mars. The fallout from that incident is just beginning: Of the two Quatros responsible, Sinclair has disappeared, and Kreed is being tracked by two Gucci assassins hired by the Martian government. The Merk now psychically reaches out to Michana - the youngest daughter of the late General Loomis, bent on revenge. Nexus doesn't have the luxury of worrying about any of this, though . . . the artificial black hole known as the Gravity Well is on the verge of collapse, which endangers the entire solar system! He and Judah Maccabee set out to appeal to the one creature who can manipulate black holes . . . Ashram, resident of the Bowl-Shaped World. The only time the duo encountered this strange world, they were with the likewise bizarre Badger! And speak of the devil . . .

Horatio, Judah, and the Badger have survived their reentry of the Bowl-Shaped World. As they head from outer rim to inner city, the threat that prompted this journey worsens: the Gravity Well is nearing collapse. The Web's population is evacuating in a panic, hoping to escape the artificial black hole. By the time this installment of Baron and Rude's celebrated sci-fi series comes to a close, the desperate trio will fight a powerful, fusionkasting tyrant in mortal combat, Kreed the Quatro will be sentenced to death for the Mars massacre, and Horatio will hang up the Nexus mantle once and for all!

Horatio has resigned his duties as Nexus, and the Merk has reassigned them... but to the Loomis sisters, who have been out for vengeance ever since Horatio assassinated their father. However, the staggering power that comes with being fusionkasters corrupts quickly, and Lonnie is so unnerved by her sisters' homicidal behavior that she escapes to the planet Procyon - home to none other than the always-scheming Ursula X. X. Imada and her and Horatio's twin daughters, Scarlett and Sheena. And when Sundra learns that Stacy and Michana are gunning for Horatio with Nexus powers, she decides to kill the Merk and damn the consequences - even if that means dooming Ylum!

History professor Stanislaus Korivitsky has been chosen by the Merk to inherit the role of Nexus, fusionkasting executioner of mass murderers. Far saner than his predecessors, Stacy and Michana Loomis, Stan immediately kills his first target and then sets off for A.J. Cronin - megalomaniacal CEO of a massively influential (and less than ethical) multiplanetary company, the Scorporation. But when A.J.'s terrifying single-mindedness outlives his own body, Stan, Horatio, and Sundra face-off with an unstoppable hunter/killer in a high-speed subzero chase... and if they survive, the antitechnology zealots of the Elvonic Order have a serious bone to pick with the new Nexus.

Saved from certain death by Sundra's shrewd business dealings, current Nexus Stan Korivitsky attempts to pick up where he left off: creating the University of Ylum and pursuing a relationship with Sonia, a former mole within the Elvonic Order. However, when the latter attachment is violently severed, Stan throws himself into his Nexus work with such brutal and indiscriminate fervor that even Ylum is forced to cut ties! Enter the Bad Brains, twisted Head-like beings who are all too willing to provide Stan fusionkasting powers in exchange for him enacting their vengeance. Meanwhile, a well-kept secret of the long-absent Merk is uncovered, the antitechnology god Elvon imperils Ylum, and Horatio's extended soul-searching travels come to a surprising conclusion.