Around 18 BBY, Clone Commander "Mayday", who had been stationed at the Imperial Depot on Barton IV for more than a year, requested reinforcements after his squad had taken heavy casualties from fighting off local insurgents. After thirty-six rotations had passed, Clone commando CT-9904 "Crosshair" and at least three clone troopers were placed under the command of Imperial lieutenant Nolan and dispatched to Barton IV to reinforce Mayday and his surviving squad.
Upon arrival, Nolan and Crosshair found Mayday and two other clones, Veetch and Hexx, in possession of Imperial cargo. Mayday expressed annoyance at the late response from the reinforcements, and confirmed that the three of them were the only remaining survivors. Nolan was displeased with the clone's efforts and disrespectful attitude, and stated that he was now in charge of the operation until the cargo was transported elsewhere. Nolan walked off, leaving Mayday and Crosshair to acquaint themselves with each other.
Later, a group of insurgents attacked the Imperial Depot, blowing up a Rho-class transport shuttle and stealing some of the cargo. Crosshair shot and injured one of the insurgents, but they managed to flee the depot. Veetch and Hexx did not survive the attack. Despite the low number of troopers remaining, Nolan sent Crosshair and Mayday to retrieve the stolen cargo. The two clones requested TK stormtroopers as backup but Nolan refused to leave the depot unguarded.
Crosshair and Mayday travelled through some caves, following a trail left by the insurgents. Crosshair accidentally stepped on a pressure mine, though Mayday was able to disarm it safely. When the two reached the insurgent camp, they used an Electro Magnetic Pulse grenade to stun some of the insurgents, then engaged in a shootout with the rest. Crosshair shot a pile of pressure mines to eliminate a large number of insurgents and end the combat. After finding the stolen goods, the two discovered that the cargo that was being contained was TK stormtrooper armor. Mayday was frustrated by how the clones were being mistreated and replaced after all they had done during the Clone Wars.
An avalanche, likely triggered by the battle that had just ensued, then engulfed Crosshair and Mayday, though they were able to climb out of the snow. Mayday told Crosshair to leave him behind, but Crosshair helped him up and the two wandered the freezing landscape until they made it back to the depot.
Nolan met the two survivors, but refused to help them when they asked for medical assistance. Mayday succumbed to the icy conditions, and died by Crosshair's side. Infuriated, Crosshair told Nolan that he could have saved Mayday, but the lieutenant simply said that Mayday had served his purpose and that the clones were expendable. Nolan began walking away until Crosshair called him back, at which point he turned back around to face Crosshair, who shot and killed the lieutenant. Four TK troopers then rushed to the scene, as Crosshair collapsed from exhaustion.
After the ordeal, Crosshair awakened to find himself in an operating chamber in the presence of Emerie Karr. Crosshair asked where he was, but Karr avoided the question and said that the doctor would come for him in time. She then told the clone to cooperate in order to have a chance of survival shortly before he fell unconscious after an injection.
Some time later, Crosshair was brought from his detention block into the same operating chamber he was in before and met Doctor Royce Hemlock. The doctor asked for his cooperation in locating Clone Force 99 in exchange for a clean slate. Crosshair denied the offer and was tortured by an IT-O Interrogation Unit. Before Hemlock could interrogate the clone further, he was notified by Scalder that an attack happened on one of their transport ship from Balmorra and left. Karr later ended the torture procedure to check Crosshair's condition to which he took that as an opportunity to escape from the facility. He took a blaster from one of the TK stormtroopers and shot the two stormtroopers that guarded the chamber. Karr warned Crosshair that it was impossible for him to leave, he ignored the warning and stunned her.