In the distant future, humanity is united under the Terran Federation. In this society, the only way to earn franchise and full citizenship is through volunteering for “Federal Service” in the military. Despite his Father’s wish that he remain a civilian and become involved in the family business, Johnnie Rico volunteers shortly after his 18th birthday, inspired by his friends Carl and Carmen and by his desire to achieve citizenship. Based on a letter of recommendation from his History and Moral Philosophy teacher, Mr. Dubois, Johnnie is assigned to the Mobile Infantry. These foot soldiers wear special armored suits that enhance their strength, speed, and armament while protecting them from enemy fire.
Johnnie goes to Camp Arthur Currie on the northern prairies for his basic training, along with 2,009 other male recruits. They learn how to fight with everything from bare hands to simulated atomic bombs. The instructors intentionally make the training regimen as challenging as possible to weed out of the group those men who won’t make capable soldiers because of their age or temperament. Johnnie himself nearly resigns during the “hump” of his training. Around this time, another recruit—Ted Hendrick—both disobeys Sergeant Zim’s orders during a training drill and strikes him, giving him a black eye. Hendrick feels that the training and discipline are unfair and complains to the Battalion Commander, Captain Frankel. His admission of insubordination leads to a field court-martial, after which he is dishonorably discharged and publicly flogged.
Just as he is about to hand in his resignation, Johnnie receives a letter from Mr. Dubois, who expresses pride in Johnnie’s character and choice to volunteer. Bolstered by this vote of confidence, Johnnie decides to complete his term. The remaining challenges of training can’t break his resolve to finish, even when he himself is flogged for actions during a training drill that would have cost the life of a teammate in real life. Although Johnnie earns the maximum administrative punishment of five lashes, he gets off light compared to another recruit named Dillinger. Dillinger deserted Camp Currie two days into basic training; while he was gone, he kidnapped, tortured, and murdered a little girl. When he’s returned to the M.I. for punishment, he’s dishonorably discharged and publicly hanged until he’s dead.
Once Johnnie and the recruits move from Camp Currie into the mountains for advanced training in the M.I.’s suits, they’re given more freedom and can even travel to nearby cities on “liberty.” Johnnie visits Vancouver and Seattle with two other recruits, Kitten Smith and Pat Leivy; in Seattle, the three are attacked by resentful civilians. Realizing how easily they defeat these men shows Johnnie how much he’s already changed during his training.
By the time Johnnie graduates basic training and joins Willie’s Wildcats as a private, the Terran Federation has moved from peace to a state of hostilities with two alien species called the “Skinnies” and the pseudo-arachnids or “Bugs.” The Bugs, a species connected by a hive mind, attacked Buenos Aires. Johnnie makes his first combat drop in “Operation Bughouse,” a Federation attack on the Bugs’ home world. “Brain” Bugs coordinate the attacks of their lethal warriors, catching the M.I. off guard. Johnnie barely makes it off the planet alive; so many of the Wildcats die on Klendathu that the “orphaned” survivors are reassigned. Johnnie finds himself in Rasczak’s Roughnecks, where he quickly finds a family among the other men in the unit.
Johnnie is happy in the Roughnecks until he receives a letter from home telling him that his Mother had died in Buenos Aires. Assuming that his Father died there too, Johnnie finds himself orphaned. Shortly after this blow, Lieutenant Rasczak dies on a mission while rescuing a private. Military discipline and duty save the Roughnecks from their grief; despite their devastating personal losses, they must continue to behave like professional soldiers as the war continues. When the Roughnecks visit Sanctuary—a colony of the Terran Federation—for R&R, Johnnie’s friend Ace talks him into making a career out of the army and taking the placement test for Officer Candidate School.
Just as Johnnie detaches from the Roughnecks for OCS, he is reunited with his Father; some last-minute business kept his Father home from Buenos Aires during the Bug attack. Following his wife’s death, Johnnie’s Father left his business in an associate’s hands and volunteered for Federal Service, requesting an assignment to the M.I. His first unit, like Johnnie’s, had been decimated in a combat drop, but when he was reassigned, his request to join the Roughnecks was honored. Johnnie remains on Sanctuary for OCS while his father boards the Roger Young to ship out with the Roughnecks.
At OCS, Johnnie receives a second training in History and Moral Philosophy under Major Reid. If high school H&MP teaches a teenager why a soldier should fight (to lay down his life between his home and the enemy), the OCS version elaborates on the purpose of violence in human history as a tool of evolution and covers the history of the current political system (in which only veterans can earn the right to vote and control the government). The final assignment of OCS is an apprenticeship cruise where the temporarily commissioned officers are battle-tested in the field.
Johnnie’s apprenticeship cruise is with Blackie’s Blackguards. Because the lieutenant who should be mentoring Johnnie has fallen ill, Captain Blackstone himself takes Johnnie under his wing, helping him to develop a more mature approach to his soldiering. With the Blackstone’s best Fleet Sergeant to assist him, Johnnie drops onto Planet P in command of a platoon for the first time. Their mission in “Operation Royalty” is to bleed the Bug forces dry enough that they can access the Bugs’ tunnels and try to capture some of their brain caste or queens. When the Bugs overrun Johnnie’s platoon, the Sergeant—who turns out to be Johnnie’s old instructor, Sergeant Zim—sees an opportunity to go down into a hole and captures a brain Bug; Johnnie and the rest of the men follow after to rescue him.
Johnnie is wounded by falling debris in the tunnels and wakes up aboard a Federation ship on its way back to Sanctuary, where he finishes OCS, is commissioned a second lieutenant, and is reassigned to the Roughnecks to serve under Lieutenant Jelal.
Some years later, after Jelal has been wounded severely enough to retire from combat missions, Johnnie commands the Roughnecks—now “Rico’s Roughnecks”—as they prepare to begin the Federation’s final assault on Klendathu.
