On the Planet Garel, Hera sent out two fellow Rebels to pick up fighter parts in the market, just as Sabine, Ezra and Chopper showed up. Hera had a mission for Sabine: find the courier who had secret information, pick it up and transport it to the Havoc Outpost. She said the information this courier was holding was very important, so she had to get it through. When Sabine asked what this courier looked like Hera had no clue, but knew he would respond to the given code phrase "It’s a long way to Alderaan". With orders understood Sabine headed out to meet with the courier, with Ezra and Chopper as backup. On the way, Ezra spoke to Sabine about how he saw her as a loner, because she usually handled her missions alone and preferred to be alone. As he went on, Sabine spotted a marking she appeared to recognize painted on a wall. But then she regrouped with Ezra and the three of them made it to where they were to meet the courier. As passengers departed from arriving shuttles, Ezra and Sabine tried the code on each passenger and on each civilian that passed them. Apparently nobody responded to the phrase and a few awkwardly walked away. Hours past, the hanger was closing and Ezra and Sabine had still not found the courier. Finally they discovered the courier to be a Gonk Droid called EG-86, who came in with the cargo. They also discovered that someone else was after the courier as well. A bounty hunter who Sabine identified as Ketsu Onyo.
Ezra learned from the two of them that they had a history together, as they were both in the Imperial Academy on Mandalore until they decided to escape and become bounty hunters. According to Sabine, they had plans to join the criminal syndicate known as the Black Sun, but Ketsu got greedy and left her for dead while she alone became part of the Black Sun. Ketsu told Sabine she would have been better off dead than joining the Rebellion. She even learnt the Empire had put a bounty on her, however she didn't intend to collect on it as her main priority was the courier. Sabine warned Ketsu that she wouldn’t let her take him, and just before the two were tempted to take on one another they were interrupted by Stormtroopers. They reminded them the hanger was closed and instructed them to leave, but Ketsu responded by shooting at them, and a gunfight occurred. As more troopers showed up, Ezra instructed Chopper to get EG-86 onto a nearby shuttle while he, Sabine, and Ketsu held off the Stormtroopers. As soon as the droids were on board, Sabine and Ezra joined them. Chopper shut down the pilot droid and Sabine powered up the engines. But as they took off, Ezra fell overboard and was left behind. Meanwhile the Stormtroopers surrounded Ketsu and held her at gunpoint. Then after ordering her to drop her weapons, Kestu suddenly attacked and took out the troopers in hand to hand combat. Then she retreated, jumping onto a departing shuttle and onto the roof where her ship, the Shadow Caster, was waiting.
Meanwhile, Sabine, Chopper, and EG-86 were now out in space, and despite leaving Ezra behind they proceeded with the mission in getting EG-86 to the rendezvous point. Then just before making the jump to hyperspace, they detected Ketsu’s ship approaching. She came up from behind and opened fire on the shuttle, knocking out their hyperdrive. Sabine could guess what Ketsu’s next move would be and ordered both droids to lock their feet down. Ketsu came up beside Sabine’s shuttle and shot the side door open, causing a haul breech. Chopper got sucked into the vacuum of space but EG-86 and Sabine got trapped in the doorway. With a bit of a struggle, Sabine managed to activate the force field, sealing the breech. Ketsu came up face to face with Sabine’s shuttle and made contact. She threatened to blow her up unless she surrendered the droid. Little did she know that Chopper, after a moment drifting in space, was on her ship and proceeded in sabotaging her weaponry. Sabine saw this and kept Ketsu distracted long enough for Chopper to disable her main cannon.
While Ketsu expressed how proud she was to be part of the Black Sun, Sabine only showed disgust for almost having that life, as she knew the Black Sun were slavers and assassins who didn’t care about anything but body counts and quotas. They would also kill their own for a profit. After Sabine again refused to hand over the droid, Ketsu regretfully opened fire on her old friend, but thanks to Chopper the guns were disabled. Sabine bid her farewell and hit the thrusters with Chopper in follow, but Ketsu captured him in a tractor beam and held him hostage. Sabine turned back and docked with the Shadow Caster, agreeing to make a trade. Meeting face to face, Ketsu could see that Sabine was still not willing to give up the courier. She offered to split the bounty with her if she handed over the droid, but Sabine told her she was no longer into making profits as she now part of the Rebellion's fight against the Empire. Ketsu showed little confidence that the Rebellion could overthrow the Empire and told Sabine it was foolish to even try. To her survival was what really matters and people could not be trusted.
Sabine told Ketsu the Rebellion gave her a second chance in life. Back when she was only out for herself, she met good people who helped her become more than what she use to be and fight for a right cause. She forgave Ketsu for abandoning her and offered her a second chance. Just then, they received a transmission form an approaching Imperial Vessel that had been tracking down the stolen shuttle and threatened to open fire if they tried to flee. This issue forced Sabine and Kestu to work together once again.
As the Imperial Vessel approached, Sabine had a plan and instructed Chopper to overload the hyperdrive on the shuttle. Then she contacted the Imperial Vessel, warning them that their ships had suffered severe damage and were in danger of self-destruction. The Imperials scanned them and confirmed Sabine’s report. The commanding officer gave Sabine and Ketsu two minutes to stabilize the situation before moving in to dock. Ketsu began to see Sabine’s plan. She was going to blow up the shuttle, giving them the time they need to escape. Using explosives stored on the Shadow Caster, Sabine planted them all over the shuttle ready to blow. She then reactivated the Pilot droid and instructed it to take emergency protocol before retreating to the Shadow Caster.
The Imperials noticed the shuttle was powering up and began to open fire. They hit the docking tube and Sabine got knocked out by the blast. Ketsu was prepared to make the getaway but the droids refused to leave Sabine behind. Two against one, Ketsu rescued Sabine as the shuttle attempted to rip away from attachment with the Shadow Caster. Finally everyone was aboard and the Shadow Caster detached from the Shuttle, but both ships got caught in the Imperial’s tractor beam. But then the explosives aboard the shuttle went off and destroyed the vessel, colliding with the Imperials in the process. They lost hold on the Shadow Caster and the ship escaped to hyperspace.
Afterwards, Sabine, Ketsu, and Chopper arrived at Havoc Outpost and delivered EG-68 into safe custody for Bail Organa via R2-D2. They then returned to Garel and landed where Hera and Ezra were waiting for them. Hera congratulated Sabine on a successful mission and thanked Ketsu for her assistance. Before going their separate ways, Sabine thanked Ketsu for saving her and told her if she ever thought about helping the Rebellion she would be welcomed. Then after shaking on it, Ketsu boarded her ship and departed as Ezra and Sabine looked on.
- Taylor Gray as Ezra Bridger
- Tiya Sircar as Sabine Wren
- Vanessa Marshall as Hera Syndulla
- Gina Torres as Ketsu Onyo
- Steven Blum as EG-86 / Dispatch / Imperial Technician
- Stephen Stanton as Imperial Technician / Pilot Droid / Stormtrooper #1
- Dave Filoni as Rodian / Stormtrooper #2
- Blood Sisters is the first episode in which neither Kanan nor Zeb appear.
- Early versions of the script had C-3PO acting as the courier, but this concept was discarded as the writers felt having such a major character present interfered with Sabine and Ketsu's interaction.
- The Shadow Caster, Ketsu's ship, is a remodel of the starship that would have been used by Asajj Ventress in Star Wars: The Clone Wars.
- The Starbus shuttle in this episode is a GX1 Short Hauler, a model which has previously appeared in The Clone Wars as well as various Star Wars Legends works.