The Zephyr Campaign takes place on a frozen asteroid.
Episode 21: "Ice-Olation" Ice Asteroid: Day 1Edit
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. Just as they are coming in for a landing, tiny flame-breathing bugs, Firefries, hatch from Zander's skin. The ship crashes, badly damaged, but there are no serious injuries. Teams are sent out to locate the Sequoia. One team, Razak and Doc, falls into a subterranean network where they are attacked by marshmallow-like Leeches. Another team, Brutto and T'Phai, find themselves in a battle with adult, human-sized Firefries. Razak and Doc, joined by Dizzy and Gossard from the ship, join in this battle. Meanwhile, the third team, Carmen and Rico, is buried by an avalanche, and beneath the snow they share some intimate moments. Dizzy saves them. All return to the Zephyr, where Higgins awaits with the recovering Zander. They finally realize that they're on the wrong asteroid; the Sequoia awaits them elsewhere. The Zephyr is unflyable and its communications system is down, so the Roughnecks are trapped with little hope of rescue. But they discover that the asteroid contains the bio-weapon they came to search for. The wrong asteroid has turned out to be the right asteroid.
Episode 22: "Mixed Signals" Ice Asteroid: Day 2Edit
The Zephyr remains crash-landed on a frozen asteroid. A team is sent out to collect Toxin B-3, a potent bio-weapon that they've found here (to their surprise, since it was supposed to be found on another asteroid entirely), while Gossard and others remain at the ship to try to get the communications system working to send an SOS... and to protect the ship from Firefries, fire-breathing bugs that the Roughnecks accidentally brought to the asteroid as eggs. The collection team fights Leeches, aggressive amorphous blobs, inside a cave; in the aftermath of the battle they discover that the Leeches are the source of the Toxin B-3. But while collecting them the team finds itself at the mercy of a hurricane-force wind coming from inside the cave. The wind blows Carmen away, and the team fears for her life. The episode climaxes in a massive battle with the Firefries around the ship. When it's over, Gossard is able to send a SOS, and Carmen returns. It looks like help is on the way.
Episode 23: "Hot Ice" Ice Asteroid: Day 3Edit
The Roughnecks are crashed on a barren asteroid. A science vessel, the Sequoia, comes to their rescue but it crashes too. They set out to find it. Eventually it is discovered by Zander and Higgins, but Zander is captured by the bugs - Firefries - who have taken it over. When the rest of the Roughnecks get to the Sequoia, they find Zander miraculously alive but deranged. They return to their own ship, the Zephyr, with the Sequoia's fuel cell. The Zephyr is attacked by Firefries but, with the new fuel cell, manages to take off. But one of the Firefries has managed to get aboard, and it explodes, causing the Zephyr to crash again.
Episode 24: "The Inside Story" Ice Asteroid: Day 4Edit
Their ship, the Zephyr, crashed again on the ice asteroid, the Roughnecks are running out of ammo to fight off the attacking Firefries. In order to give Gossard time to set up a poison gas perimeter around the ship, Rico, Dizzy and T'Phai lead the 'Fries on a wild goose chase. They are trapped and seem doomed, but Zander, who's been acting strangely since his own capture by the Firefries, appears and leads the Fries away like a Pied Piper. The Roughnecks think Zander's dead, but he returns to the ship -- physically okay, but even more deranged. As the battle continues, Razak tells Rico he's been promoted to Corporal. An earthquake on the rapidly changing asteroid sends the Zephyr careening into a crater. After a wild ride, the ship ends up deep inside the asteroid. With air on the ship running low, Bruto and Doc go out into the surrounding tunnels to search for a source of oxygen. They barely make it back to the ship, but they bring news that they think they've found some oxygen. Doc has some other news: he thinks that what they're inside is not an asteroid but some kind of living thing.
Episode 25: "The Ice Men Goeth" Ice Asteroid: Day 5Edit
The Roughnecks' ship, the Zephyr, remains trapped inside what they now know is a giant bug. A team consisting of Rico, Brutto, Dizzy and Doc has been sent out to retrieve air. After Rico rescues Brutto from a fall, the two of them become separated from Dizzy and Doc who succeed in tapping an air source but are swept away by one of the bug's arteries. Back at the ship, Zander is becoming more unhinged. He inadvertently gives Gossard the idea of using the Firefries as fuel for the Zephyr. Rico returns to the ship with Dizzy and Doc just as it's taking off. Zander attempts to sabotage the ship but is foiled. The Zephyr escapes from inside the bug, and the bug is blown up by the Zephyr's auto-destruct mechanism.
During this campaign Firefries, the Ice Bug (a totally new bug species to SICON), and Space Leeches are encountered by the Roughnecks for the first time.