In 3 BBY, the Phoenix Cell decided to establish a new route through the Lothal sector. At the recommendation of the Mandalorian Sabine Wren, the rebels visited the Concord Dawn system to seek safe passage from the Mandalorian Protectors, a Mandalorian faction that had sided with the Galactic Republic during the Clone Wars. However, the Protectors, under the leadership of Fenn Rau, had aligned themselves with the Galactic Empire and attacked a rebel delegation led by Phoenix Leader Hera Syndulla.
Hera was badly wounded during the attack. As a result, the rebels abandoned diplomacy and contemplated military action against the Protectors. Sabine managed to track the Protectors' Fang fighters to a base on the third moon of Concord Dawn. Sabine advocated destroying the Protectors' starfighters in order to eliminate their threat to the rebellion. The Jedi Kanan Jarrus supported Sabine's plans but insisted on going alone with the astromech droid Chopper, who piloted the Phantom, an auxiliary starship. In secret, Kanan planned to negotiate a second time with Fenn Rau in order to give the Protectors a second chance to join the rebellion as allies.
While approaching the Concord Dawn system, Chopper informed Kanan that Sabine had stowed aboard the Phantom. After emerging from her hiding place, Sabine and Kanan discussed their differences. While Sabine was intent on avenging the wrong that Fenn had inflicted on Hera, Kanan still wanted to seek a diplomatic solution to the conflict. In the end, Kanan allowed Sabine to destroy the Fang fighters only on the condition that his peace talks with Fenn failed. Chopper dropped the two rebels outside the Protector's camp on the third moon of Concord Dawn before retreating to the skies. After landing, Kanan and Sabine spotted the Protectors receiving supplies from an Imperial shuttle.
A shootout ensued despite Kanan's peaceful intentions
While Kanan followed Fenn Rau into a building, Sabine headed to the starfighter airfield and began planting explosives onto the Fang fighters. Fenn quickly sensed Kanan's presence and allowed the intruder to reveal himself. In an attempt to establish a rapport with Rau, Kanan introduced himself as a Great Jedi Purge survivor who had taken part in the Third Battle of Mygeeto. Rau had commanded Skull Squadron during that battle and had saved the lives of Kanan, his late Master Depa Billaba, and numerous Clone troopers. Kanan then attempted to convince Rau to realign the Protectors with the rebellion. However, Fenn refused believing that the rebels had a poor chance of success against the Empire.
Meanwhile, Sabine managed to attach explosives to seven of the Fang fighters before she was spotted by two Mandalorian sentries. After identifying herself as a member of Clan Wren (an enemy of the Protectors), Wren invoked her right to seek justice through combat. Kanan's negotiations with Fenn were interrupted by news that his men had captured another intruder who had invoked the rite of justice through combat, an ancient Mandalorian tradition that had not been invoked during the Age of the Empire. Fenn led a reluctant Kanan to the airfield where the duel was to take place.
Despite Kanan's calls for restraint, Sabine was adamant on proceeding with her plan and urged the Jedi to trust her. Before the duel, Sabine condemned Fenn for attacking and wounding Hera. Rau admitted attacking Hera but insisted that it was not personal. As Fenn drew his blaster pistol, Sabine shot it out of his hand and blew up seven of the Fang fighters with her explosives. Kanan and Sabine then exchanged fire with the Protectors during the ensuing skirmish. Meanwhile, an enraged Fenn climbed aboard the remaining Fang fighter and attempted to attack the rebel fleet.
However, Kanan managed to grab onto the starfighter as it climbed into the skies. Despite Fenn's efforts to shake off the Jedi intruder, Kanan managed to use his lightsaber to slice through the cockpit and disable the control console. Meanwhile, Sabine rendezvoused with Chopper and the two flew into the skies to pick up Kanan. Following a fist fight, Kanan managed to knock the Protector of Concord Dawn unconscious and carry him onto the Phantom.
Once aboard the Phantom, the three rebels headed back to rejoin the Phoenix fleet in space. As soon as Rau began to stir, he was contacted via comlink by his men. Kanan ordered Fenn to answer the comlink. By that point, the Protectors had amassed reinforcements and were preparing to pursue the rebel intruders. However, Fenn ordered them to stand down and to allow the rebels safe passage through the Concord Dawn system. He also instructed them to hide his capture from the Empire.
Rau was ultimately delivered to the Rebels in unwilling fashion
Fenn Rau accompanied Kanan and Sabine back to the Phoenix fleet where he was taken into custody by the rebels. Due to his combat skills and training, the rebels regarded Fenn as a "reluctant recruit." Fenn himself regarded the arrangement as an "alliance of necessity." Sabine's conduct during the mission won her the praise of Hera, who praised the younger rebel for finding an acceptable way to resolve the Concord Dawn impasse. By demonstrating their strength, the Phoenix rebels were able to establish a new lane to the Lothal sector that went through the Concord Dawn system.
The mission to the third moon of Concord Dawn served as the climax of the Star Wars Rebels episode "The Protector of Concord Dawn," which premiered on Disney XD on January 27, 2016.