During the First Order's control of the Colossus platform on Castilon, Kazuda Xiono, a Resistance member acting as a secret agent, initiated an operation to take down the First Order's communication blocker on top of Doza Tower, enabling him and his comrades to get in touch with the Resistance.
Prior to the Attack on Tuanul, Poe Dameron and Kazuda Xiono, both Resistance aviators, embarked on an investigative mission into First Order operations within the Dassal system. There, they found that the First Order had drilled through multiple planets and annihilated the system's star. In the process, First Order forces under Major Elrik Vonreg pursued them.
Though Kaz managed to escape back to the Colossus, Major Vonreg tracked him down and identified his starship Fireball using visual data. As a result, Commander Pyre gave the order to detain Team Fireball. Kaz, who had just returned from assisting Hype Fazon, Aunt Z, Nod, and Grevel in their offworld escape, came back to discover his companions being held by Commander Pyre and his stormtroopers.
Yeager's repair station became the starting point for Yeager, Kaz, Neeku Vozo, and CB-23's escape, aided by Bucket. During the firefight, Commander Pyre shot Bucket, causing him to fall overboard. However, Tamara Ryvora, who sympathized with the First Order, chose to be arrested, believing it was a misunderstanding. Captain Imanuel Doza, the leader of the Colossus, opposed the raid on Yeager's repairs, but Commander Pyre disregarded his objections. Pyre then requested assistance from Agent Tierny of the First Order Security Bureau to interrogate Tam.
As they moved through the lower-level tunnels, Yeager and his team were chased by stormtroopers. Eventually, the four were trapped above a trapdoor. Before the First Order could apprehend them, the trapdoor opened. Kel, Eila, and the Chelidae, who lived on the engineering deck, rescued Yeager, Kaz, Neeku, and CB-23. They also found Bucket, who had been caught in the Chelidae's nets.
After getting back together, Kaz decided to send a message to the Resistance asking for help, free Tam, and remove the First Order from the Colossus. Meanwhile, Agent Tierny took advantage of Tam's positive feelings towards the First Order by claiming that they stood for peace and order. She also revealed that Kaz was a Resistance spy, aiming to create conflict between Tam and her friends.
Back in the engineering deck, Kaz devised a plan to disable the First Order's jammer on Doza Tower by submerging the Colossus underwater. Despite Yeager and Neeku thinking Kaz's plan was crazy, they agreed since there were no other options. Yeager instructed CB-23 to inform Captain Doza, who supported the New Republic, and arranged for him to seal the hatches to prevent the station from flooding.
Putting their plan into action, Neeku reduced the ballast and increased the downward thrust, while Yeager shut down the turbines. As the Colossus sank beneath the sea, Captain Doza instructed the citizens to go to their homes and sealed the main hatches. Once the station was submerged, Kaz, Yeager, and CB-23 swam up and climbed onto Doza Tower. They disabled the jammer, and Kaz had CB-23 send a transmission to General Leia Organa, the leader of the Resistance.
Kaz successfully sent a message to General Organa, informing her about the situation on the Colossus and requesting assistance. Shortly after, Commander Pyre emerged from the hatch with several stormtroopers. By this point, he and Agent Tierny had realized that the sinking of the Colossus was a deliberate attempt to hinder their search for the fugitives. Following a struggle, Kaz and CB-23 managed to escape, but Yeager was captured.
Kaz's transmission reached General Organa, who apologized that the Resistance couldn't send reinforcements but provided the coordinates of their new base. She also assured Kaz that he wasn't alone and that the Force was with him. Despite facing overwhelming odds, Kaz, Neeku, CB-23, Kel, Eila, and the Chelidae formed the Colossus resistance cell.
Kaz's transmission also reached Kragan Gorr's Warbird pirates. Synara San, whom Kaz had befriended and helped escape previously, received the message. Having completed his mission to contact the Resistance, Kaz set out to rescue Tam and Yeager. Meanwhile, Commander Pyre ordered Captain Doza's arrest for not following orders.
The mission to contact the Resistance was first shown in the Star Wars Resistance Season One episode "Descent," which premiered on March 3, 2019.