The Roughnecks are ordered to the planet Hydora after a transport bug is seen leaving Pluto. The Roughnecks mission is to establish if Hydora is the bug home world or not. While there they receive an extremely disturbing message.
Rico is reunited with Carmen when a retrieval mission goes wrong. What starts as a minor operation on Hydora develops into a full blown battle as Bug numbers turn out to be far higher than expected.
The Roughnecks are sent on a seemingly routine recon mission of the planet Tophet to determine if it can be used as a waystation for S.I.C.O.N. to the rest of the galaxy.
When a Cyborg named Chas "Cybernetic Humanoid Assault System" is assigned to the Roughnecks, he is befriended by Higgins, who views the robot as a kindred outsider.
Colonel T'Phai the Skinnie who was partially responsible for Carl's fried brain joins the unit just as they're assigned the task of taking Zegema Beach as part of the Tesca Nemerosa campaign.
After Gossard receives a minor injury, Rico is assigned a marauder suit for the Roughneck's next mission: they're heading upriver to capture a Brain Bug.
Rico hovering in a coma between life and death flashes back to High School with Dizzy, Carl, Carmen and Razak, and Basic Training with Drill Sergeant Zim.
Returning from a combat mission in a retrieval ship, the Zephyr, the Roughnecks are re-routed to an asteroid to join scientists from another ship, the Sequoia, in a quest for a bio-weapon against the bugs.
Aboard the Valley Forge on a long trip to their next campaign, the Roughnecks have drawn watch as most of the ship's crew rests in suspended animation.
While at a temporary camp on Klendathu, the Roughnecks are attacked by a new and dangerous form of arachnid, an Imposter Bug that approximates the size and shape of a human.
After a long day of battling Bugs, the Roughnecks are called to a mission briefing only to find themselves in the presence of Sky Marshall Sanchez himself.
The Bug Queen has survived a battle on Klendathu, and is headed for Earth. When the Troopers discover that the bugs have cloned human DNA to be able to take human form, they realize that extermination is going to be even more difficult.
When the Bug Forces launch a devastating surprise attack on Buenos Aires, nearly destroying the city, the Roughnecks are sent in as part of a massive ground troop assault.
The bugs have tunnels underneath San Francisco. Military Intelligence wants to blow up the city to get the bugs, but that would also kill all the civilians in the area. The Roughnecks and Walker's Team come up with an alternate plan to deal with the bugs. The city will be saved, but one will pay the ultimate price.
With no LT the Roughnecks are to be disbanded. Before they break up, they fulfill the last request of their C.O. SGT Brutto and General Redwing pay their respects as well. They come across some bugs, Redwing and Higgins are captured. Outnumbered and unable to call for support, the Roughnecks must mount a rescue and destroy the bugs.
The Roughnecks are assigned to protect Oahu. They get 2 new members to their squad. Max Brutto, SGT Brutto's son, and SGT Zimm. Rico's not sure about his abilities as a leader. Soon he'll learn how his former C.O. had a bigger hand in his life than he realized.
