A Rebel transport ship, escorted by A-Wing Starfighters, was on a supply run for the people of Teralov. However, the transport was suddenly ambushed and attacked Imperial forces before reaching its destination. TIE Interceptors were deployed and engaged the Rebels. Despite their best effort to fight back, the Imperials were victorious, leaving no survivors. Word of the attack got out to the Rebellion which left them concerned. At the rate it was going they would have no pilots left to fly for the Rebellion. However, Comander Sato had received word from a Fulcrum agent that there were a few Imperial Cadets at the Skystrike Academy who wished to defect to the Rebels. Their names were unknown but required assistance to escape. Hera handed the mission over to Sabine, who would go undercover as one of the Cadets attending Skystrike. Ezra and Kanan meanwhile would wait in the shadows until they were needed to help her and the defectors escape.
Later, Sabine arrived at the Skystrike Academy with other TIE Pilot cadets. She almost did not get past security when her ID card did not check in, but managed to get through when she got them to check it again after she cleaned it. Sabine, under the name of "Ria Talla", was now inside the Academy among with the other cadets. The next day, Sabine took part in simulated combat training with another cadet known as Wedge Antilles. Using Simulator Pods, Sabine and Wedge intercepted four Y-Wing Starfighters. Each pilot took out two, the enemy was eliminated. Next they were ordered to intercept and unarmed transport ship and destroy it. Sabine was reluctant to carry out her orders, but then they were suddenly taken out by a simulation of the Ghost. The simulation was over and Sabine and Wedge emerged from their pods. Sabine was the first to complain about the ship used to attack them, only to be told by Captain Vult Skerris that Rebel forces would fight with any ship using any methods necessary to undermine the Empire’s authority. A lesson that the cadets should imprint; follow orders without question or their insubordination would get them killed.
Skystrike Academy received an unexpected visit from Governor Pryce and Agent Kallus who have come to inspect the cadets. They had word about the cadets who were planning to defect to the Rebellion. Despite Instructor Goran’s assurance of the loyalty of his cadets’ Governor Pryce none the less would still carry out the investigation with full cooperation. Meanwhile, Sabine overheard three cadets having a private conversation. They were worried about being discovered as traitors, which made Sabine suspect that those three pilots were the defectors who wanted to escape. Sabine followed Wedge to the hanger and they have a private conversation about their choices in joining the Empire. Wedge only joined because he thought it would be more exciting than hauling parts across the galaxy like he use to do. But after realizing what he was being trained to do, Wedge’s view on the Empire had changed. He would rather fight against the Empire than serve it. Sabine reveals herself as the Rebel who had come to help him and his colleagues escape. She recommended that they leave immediately before they are discovered.
Meanwhile, Kallus reported to Governor Pryce that he had nearly completed his investigations and so far there was nothing out of the ordinary. So Governor Pryce decided to take a more direct approach in finding their traitors. On her orders, Instructor Goran orders Squadron twenty-two to report to their fighters for a simulated dogfight using actual fighters. On the way, Wedge introduced Sabine to two other pilots who wished to defect; Rake and Hobbie. Before boarding their fighters, Sabine told them that a Rebel ship was waiting for them and when she gives the signal they make a break for it. The cadets boarded their TIE Fighters and took off from the hanger with three TIE Interceptors in follow. As the cadets approached space, Instructor Goran informed them that they would be using numb lasers and any hit they take will be registered and scored. Then on Goran’s command, the simulated dogfight began. The cadets tried to shoot one another using numb lasers, and any pilot that was Hit was out. As the simulation went on, Sabine meanwhile was looking out for Ezra and Kanan to arrive. Their ship emerged from hyperspace and Sabine, Wedge, Hobbie and Rake made a break for it. Governor Pryce ordered them to return to base but they refused. But just as they were even close to dock with the Rebel ship, they suddenly lost their wings and power at the touch of a button back at Skystrike. Their fighters were rigged. Governor Pryce then ordered Captain Skerris to destroy one of the pods and he killed Rake. Next they moved in on Ezra and Kanan’s ship and attacked. They took on heavy damage and despite Sabine’s plea to retreat; Ezra refused to leave her behind. But apparently they had no choice and were forced to retreat, leaving Sabine and the other pilots to be captured by the Imperials.
Governor Pryce met up with Sabine, Wedge and Hobbie in the interrogation room and wanted to know which one of them was the Rebel agent. The three of them said nothing, but when Pryce threatened to torture Wedge Sabine revealed herself as the Rebel agent. Pryce has Agent Kallus escort Wedge and Hobbie to their cell while Sabine remained with her for further interrogation. Sabine was almost put in the interrogation chair, but as soon as the Stormtroopers removed her bindings she broke loose and engaged Governor Pryce in a physical confrontation. Both were equally trained but Sabine overpowered her and took out the Governor with the interrogation chair’s shock tool. She then grabbed a blaster and broke Wedge and Hobbie out of their cell. The Imperials sounded the alarm as the three of them escaped to the hanger. Sabine, Wedge and Hobbie ended up trapped in hallways when the Imperials sealed the exits, but they received unexpected help from Agent Kallus. He unsealed one of the blast doors and told them to avoid certain levels and make their way to hanger twenty-four. Sabine was cautious and asked Agent Kallus why he should by trusted, only to be told to deliver a message to Garazeb Orrelios that they were now even. Sabine, Wedge and Hobbie made it to the hanger and escaped in a TIE Bomber. However, they were pursued by Skerris. The bomber was slow, giving Skerris an advantage to keep up with them. He took two shots at them and Wedge tried everything to shake him off. Pretty soon the bomber suffered major damage, and just as Skerris was about to finish them off Ezra and Kanan returned. The bomber docked with their ship and escaped to hyperspace back to Atollon. The Rebels made it safely back to base and Wedge and Hobbie were welcomed to the Rebellion.
- Taylor Gray as Ezra Bridger
- Freddie Prinze, Jr. as Kanan Jarrus / Imperial Technician / TIE Cadet #1
- Vanessa Marshall as Hera Syndulla
- Steven Blum as Green Leader
- Tiya Sircar as Sabine Wren
- Keone Young as Jun Sato
- Nathan Kress as Wedge Antilles
- Corey Burton as Bridge Officer / Argin Relik / Rake Gahree
- David Oyelowo as Alexsandr Kallus
- Mary E McGlynn as Female Civilian / Arihnda Pryce / TIE Cadet #2
- Dave Filoni as Green Five / Imperial Officer
- Trevor Devall as Derek Klivian / Rebel Captain / Transport Captain
- Mario Vernazza as Vult Skerris
- The TIE Interceptors, first seen in Return of the Jedi, made their Star Wars Rebels debut appearance in this episode.
- This episode marks Wedge Antilles and Derek "Hobbie" Kilvian's debut appearance in the series.
- The device that Sabine takes from Pryce is a "Code cylinder", a kind of electronic access keycard. They have been visible on Imperial officer uniforms since the Original Trilogy, but their function was only elaborated upon in spinoff books and comics.
- After Sabine arrives on the station with the other cadets and they are dismissed, some of the cadets in the background start idly chatting about a new speeder model called an S-40: this seems to be a nod to a similar moment in A New Hope when Kenobi is shutting down the tractor beam, and Stormtroopers on guard duty are overheard idly chatting about VT-16's. The Sequel Trilogy included a similar nod, when in The Force Awakens on Starkiller Base two Stormtroopers are again heard mundanely discussing a new speeder model.
- Wedge's line "I can fly anything" (when asked if he can fly a TIE Bomber) also seems to be a nod towards Poe Dameron's in The Force Awakens, who gives the same exact line when asked if he can fly a TIE Fighter.
- During early development, the episode was originally titled "Darklighter" and dealt with the defection of Biggs Darklighter into the Rebel ranks, but timeline complications with his backstory meant that Wedge was the better candidate. The original plot line also indicated that Sabine would have been responsible for the checkered decoration patches on Biggs' helmet in A New Hope, as Sabine decorated part of her armor with a similar design at one point.
- Sabine's alias "Ria Talla" is a leftover name from an early version of Rogue One.