Hailing from an icy planet, Shonn Volta was a Force-sensitive female. Her father worked as a freighter pilot, while her mother was a sculptor. Upon discovering Volta's Force sensitivity, they chose to conceal her within the cargo hold of a starship, fearing detection by the Jedi Order and subsequent removal. She remained in the cargo hold until the age of ten, surpassing the age at which the Order typically considered accepting younglings as initiates. Subsequently, she pursued studies to become a hyperspace engineer, with the aspiration of plotting new space lanes to enhance the safety of travel for individuals like her father.

With the outbreak of the Clone Wars, which engulfed the galaxy, Volta's father met his end at the hands of clone troopers from the Galactic Republic seeking to seize his ship. Subsequently, the Republic severed supply lines to the Voltas' homeworld, resulting in Volta's mother succumbing to death by starvation. Around this period, Volta entered into marriage on the ice floes of her planet, only for her husband to be slain shortly thereafter as violence erupted and spread.

Volta then enlisted with the Confederacy of Independent Systems as a captain, and at some point Count Dooku provided her with an artificial heart. As a skilled sniper, she harnessed the Force to guide blaster bolts with precision to hit her intended targets. Eventually, she was tasked with assassinateing Senator Riyo Chuchi, but Jedi Master Kit Fisto and Jedi Knight Anakin Skywalker apprehended her before she could fulfill her mission. Volta's fate then led her to The Prism, where she was confined alongside other extremely dangerous individuals.

In the year 19 BBY, both the Republic and the Jedi Order were brought down by the schemes of Emperor Palpatine, who subsequently established the Galactic Empire. However, shortly thereafter, Headmaster Gentis orchestrated a coup, with the intention of eliminating the Emperor and putting an end to the Empire's warmongering policies. Palpatine sustained injuries during the attacks and was swiftly evacuated from Coruscant by Dark Lord of the Sith Darth Vader, Moff Trachta, and Lieutenant Laurita Tohm. The group transported Palpatine to the Prism, recognizing it as a location where Gentis's forces would be unlikely to discover them. While the facility's medical droids tended to the Emperor, Tohm conceived a strategy to reclaim Coruscant: with Vader's approval, they could release the prisoners to form a small army. Vader acknowledged the merit of Tohm's plan but modified it to align with his own objectives. Instead, he ordered the release of 207 prisoners into the prison yard, instructing them to eliminate anyone in sight, including Tohm and Vader.

The ensuing conflict was brutal, resulting in a rapid accumulation of casualties. Tohm found himself under attack from another Separatist, General Ur'Loach. The general had ensnared Tohm's neck with his lengthy tongue and was attempting to draw him into his expansive maw, a tactic he was known for—decapitating his adversaries with his own teeth. As Ur'Loach disarmed Tohm of his blaster and prepared to deliver the killing blow, Volta pulled the blaster toward herself and fatally shot Ur'Loach through the mouth, saving Tohm's life. Tohm expressed his gratitude, but she clarified that her action was self-serving, suggesting that by working together, they could both survive, and he could pardon her sentence.

Ultimately, only thirty-three prisoners remained in fighting condition, prompting Vader to instruct Trachta to convey to the survivors the meaning of serving the Empire. Trachta informed Volta and the others that their past transgressions were now forgiven, but the motivations behind them were not—they would now serve an institution that was not beholden to the "selfish" senators of the Republic or the Jedi Order. The prisoners knelt before Trachta and the others, but Volta remained standing. Vader commanded her to kneel as well, but she instead inquired about the necessity of the prisoners. Vader retrieved his lightsaber from his belt, but Tohm intervened, informing Volta that they had been betrayed and that her service could potentially lead to becoming an Imperial or even gaining freedom. Volta relented and knelt before the pair. Trachta then announced that their training would commence that very night.

Volta later reunited with Tohm on a platform outside the prison. There, she demonstrated her marksmanship by expertly shooting the heads off of five 2-1B surgical droids while conversing with Tohm, who was reviewing her prison files for the mission records he was compiling. Volta angrily informed him that the prison's records were incomplete and recounted the terrible actions of the Republic and the Jedi against her and her loved ones. Tohm then shared his aspiration to become a pilot, like Volta's father, but acknowledged that it was no longer possible. He then realized that Volta's experience with hyperspace study may allow them to save Grand Moff Wilhuff Tarkin, who was soon to fall into a trap laid by Gentis.

Leveraging Volta's hyperspace expertise, Tohm and Volta located Tarkin as he altered hyperspace lanes at the convergence of several trade routes. Successfully hailing his vessel, the Imperials and freed prisoners discreetly boarded Tarkin's shuttle. As they landed, Volta instructed Tohm to remain close to her.

Gentis assembled his cadets to welcome Tarkin's shuttle, planning to finally solidify his control over the Empire. Tarkin disembarked along with his stormtroopers, only to be immediately surrounded by the cadets. Gentis confronted Tarkin, expressing his desire to capture him alive for interrogation and outlining his reasons for the coup. However, Tarkin displayed indifference towards the hundreds of innocent cadets who had perished under his command. When Gentis revealed that his own sons had been killed by the Emperor's policies, Vader informed him that he would soon see them again.

Gentis looked up in horror as Vader emerged from the shuttle alongside Volta, Tohm, Trachta, and the remaining deadly ex-prisoners. Despite being outnumbered eight to one by Gentis's forces, the attackers compensated with the diverse skills they possessed. Vader unleashed a devastating Force wave while the prisoners decimated the cadets. Caul Gentis, Gentis's son, instructed Koh, a demolitions expert, to target their attackers with grenades. Volta swiftly shot Koh before he could deploy the armed explosives, causing them to detonate among the cadets, resulting in numerous fatalities.

Caul retreated among the scattered and wounded cadets until he heard Tohm call out to him. Mistakenly believing that Tohm was still on their side, he was pleased to see him, only for Tohm to fatally shoot him in the stomach. Gentis witnessed his son's fall and rushed to his side, devastated by the loss of his last child. Gentis pleaded for Caul not to die and vowed to protect him. Suddenly, he was struck by Force lightning, an attack from the Emperor himself. As he screamed and clutched his son to his chest, his body was ravaged by Palpatine's dark side power, leaving him a charred husk.

In the aftermath of the battle, all those who had remained loyal to Gentis were rounded up and executed without trial. Tohm personally oversaw the executions, allowing the bodies to accumulate as a grim warning to all who had betrayed the Empire. The Emperor rewarded Tohm for his service with a promotion to Admiral and a command in the Outer Rim Territories. Trachta also received a reward, being promoted to Grand Moff and appointed as the new Headmaster of the Imperial Academies.

Unbeknownst to Volta and the other surviving ex-prisoners who had played a role in saving the Empire, the Imperials they had fought alongside were at that very moment deliberating their fates. Trachta argued that they owed the prisoners a debt of gratitude and should honor their promises. Vader, however, advocated for their execution to prevent them from becoming future adversaries. Tohm proposed a third option, and the prisoners were informed that they would be released but would have to exile themselves to the Corporate Sector. Before their departure, they were met by Tohm, Trachta, and Vader, who reiterated the terms of their release. Nax Cirvan agreed to all the conditions, and Trachta wished him luck.

As the ship ascended over the Coruscant cityscape, it detonated, resulting in the deaths of Cirvan and all those on board. Tohm and Vader had betrayed the agreement, as well as Trachta, who was horrified by the dishonorable massacre. He vehemently protested Tohm and Vader's duplicity, but both men remained unapologetic. Tohm coldly informed the cyborg that the old ship must have malfunctioned. Disgusted, Trachta abandoned Tohm to Vader's care, no longer willing to mentor the young man.

In addition to his promotion to Admiral, Tohm successfully secured a pardon for Volta, sparing her the fate of the other prisoners. Now clad in an Imperial uniform, she was granted the rank of captain, and Tohm requested that she serve under his command during their meeting in his new apartment. Tenderly touching the burned side of his face, Volta expressed her honor at the opportunity. They were scheduled to depart for the Outer Rim the following day.

Tohm subsequently received an invitation from Vader and met the Sith Lord on a balcony high above the city. Vader inquired whether Volta had accepted her new position, and Tohm excitedly informed his new mentor that they would be leaving soon. Vader then revealed that he had one final lesson for the young man, and Tohm grew even more excited, expressing his gratitude for the opportunity to work with Vader. Vader then lifted Tohm by his uniform and declared that one should never tolerate the existence of rivals. Tohm pleaded with Vader, but the Dark Lord remained unmoved and cast Tohm from the balcony, sending him plummeting into the depths of Coruscant.