The date is October 4, 2031. A shuttlecraft arrives at the Plex Mall in Chicago from Gagaringrad, Luna (the Moon). Disembarking is Reuben Flagg, a former video program star who has been drafted into duty by the Plexus Rangers, a corporate law enforcement organization. Flagg's series, a lurid mix of action and sex titled "Mark Thrust, Sexus Ranger", continues without his involvement thanks to his being replaced by a computer generated replica of his character.
Flagg is welcomed by his superior, Hilton "Hammerhead" Krieger, chief of the Ranger station located at the Mall, which serves as a transportation hub as well as a shopping and entertainment center. Flagg is soon introduced to Krieger's daughter, Amanda, or "Mandy", and Gretchen Holstrom, proprietor of Love Canal, a night club/adult shop/brothel. Flagg also finds himself recruited to join in on that night's firefight against a gun-toting motorcycle club, or "gogang". The firefights occur at 10:45 p.m., every Saturday night, after the gogangs get hopped up on violent programming, liquor and drugs. The Rangers subdue the gogang with non-lethal weapons, specifically, "snowballs", missiles composed of concentrated Somnambutol, a sleeping agent.
Afterwards, the exhausted Flagg retires to his new quarters, only to find Gretchen seductively waiting for him.
The next morning, still sleep-deprived, Flagg finds Mandy in a café with Chicago Mayor Charles Keenan (C.K.) Blitz and his two robotic bodyguards, "Bert" and "Ernie". The mayor excuses himself and Flagg sits down. When he admits his late night activities, Mandy expresses disgust at Gretchen for already having gotten her hooks into him. They are soon joined by Krieger and Krieger's companion, a talking cat named Raul. Krieger collects Flagg to go on an air patrol over the city. On the way, Krieger tells Flagg he had arranged his tryst with Gretchen, and that he'd captured the whole thing on video.
As they pilot their gyro, or "Hicycle", amidst the many floating transmitter antennae, Flagg witnesses several ongoing firefights in the city below. They are being fought out by dozens of militant political factions known as "policlubs". The Plex allows the policlubs to engage in open combat within certain guidelines, going so far as to supply them with weapons, funds and video equipment. The Plex then broadcasts the battles, packaged as popular entertainment.
Throughout the following week, Flagg gets to know his jurisdiction. Come Saturday afternoon, he takes some time to start a journal. He recounts something of the history of the previous 35 years, since the global socio-politic-economic catastrophe that had taken place in 1996. These crises forced the U.S. government to relocate to Mars on a "temporary" basis that has yet to change. Flagg adds that despite the nation's current flaws, he grew up loving the United States and still does.
His reverie is interrupted by the arrival of Cyril Farid-Khan, leader of the Genetic Warlords gogang. Cyril tells Flagg that in exchange for a protection fee, he'll deliberately miss Flagg when firing his weapon at that night's firefight. Flagg resignedly complies.
Later, Flagg relaxes, watching video programming, and he decides to sample the gogangs' favorite, "Bob Violence". He is shocked to see that the show is loaded with subliminal messages encouraging antisocial and psychopathic behavior in its viewing audience. He further concludes that it is the catalyst that drives the gogangs to commit their weekly rampage. However, when Flagg confronts Krieger with his theory, Krieger dismisses the notion, asking Flagg why only he sees the subliminals. As Flagg walks away in frustration, Raul tells him he, too, can see them, but he's never said anything, not wanting to rock the boat.
45 minutes later, Cyril's gogang strikes. Flagg, fed up with the madness, leaps into the fray to tackle and apprehend Cyril, effectively ending the rampage. Once Cyril is behind bars, Flagg insists that "Bob Violence" be taken off the air, but Krieger refuses to take steps to do so. Mandy, eavesdropping outside, has an idea.
The following Saturday evening, Mandy enters the Ranger station and shows Krieger and Flagg a provision in the Ranger policy authorizing interruption of programming in times of civil disorder. Furthermore, she designed and had built a device to jam transmission signals. Flagg takes the unit and installs it the floating antenna that provides the "Bob Violence" feed.
Back at the station, Krieger prepares for that weekend's firefight, expecting it to be worse than ever, since he believes the gogangs will be livid at the loss of their favorite show.