A brief battle took place in 2 BBY over the planet Mykapo. The combatants included Phoenix Cell, the Galactic Empire, and Iron Squadron. Phoenix Cell and the Spectres launched an evacuation operation upon discovering the Empire's impending crackdown on Mykapo's dissenters. Iron Squadron annihilated an encountered Imperial scouting party during this effort. While the rebels were evacuating rebel sympathizers from Mykapo, Hera Syndulla, Ezra Bridger, and Sabine Wren attempted to persuade Mart Mattin and his rebel group to evacuate with them. Iron Squadron initially resisted leaving, but found themselves under assault by an Arquitens-class command cruiser commanded by Admiral Kassius Konstantine. With assistance from the Spectres and Commander Jun Sato, Iron Squadron successfully entered hyperspace and joined the larger rebellion.
During the Age of the Empire, Iron Squadron, a rebel group, emerged on the world of Mykapo. This group was led by the brother of Commander Jun Sato from Phoenix Cell. Sato's nephew, Mart Mattin, along with Gooti Terez, a Theelin, Jonner Jin, a human, and R3-A3, an astromech droid, comprised Iron Squadron. They operated from the YT-2400 light freighter named Sato's Hammer. Following Mattin's father's death, Iron Squadron lost contact with Commander Sato and continued their solitary struggle against the Galactic Empire on Mykapo.
In 2 BBY, Rebel intelligence indicated the Empire's plans to enforce martial law on Mykapo. Phoenix Squadron and the Spectres launched an evacuation effort for rebel sympathizers after receiving this warning. Simultaneously, the Empire dispatched a Gozanti-class cruiser and four TIE fighters as an advance patrol to Mykapo. The Imperial patrol then encountered Sato's Hammer and engaged it in aerial combat.
Phoenix Squadron arrived above Mykapo to observe Sato's Hammer under assault by Imperial fighters. Upon witnessing the aerial engagement, Phoenix Leader Captain Hera Syndulla dispatched the Sphyrna-class Hammerhead corvette P2 and an A-wing escort to execute the planned evacuation of rebel sympathizers from Mykapo's surface. Syndulla then redirected Phoenix Two and Phoenix Three, along with her own ship, the Ghost, to escort Sato's Hammer. Syndulla attempted to contact the freighter, but Mart Mattin, the captain, responded that Iron Squadron did not require assistance. Subsequently, Sato's Hammer released several explosive cargo containers onto the Gozanti cruiser, inflicting severe damage and compelling its retreat into hyperspace.
With the Imperial patrol neutralized, Spectres Kanan Jarrus and Garazeb Orrelios departed to assist the planetside evacuation aboard the Ghost's auxiliary vessel, Phantom II. The remaining Ghost crew docked with Sato's Hammer. Hera attempted to persuade Iron Squadron to evacuate the system with them, as the hyperdrive aboard Sato's Hammer had sustained damage. However, Mart and his followers refused to leave Mykapo, believing they could independently confront the Empire.
From Mykapo's surface, Captain Rex informed Syndulla that the evacuation of rebel sympathizers from the planet had been successfully completed. Unable to reason with Mart, Hera returned to the Ghost, intending to depart with her crew and abandon Iron Squadron. However, Jedi Padawan Ezra Bridger requested to remain behind with fellow Spectres Sabine Wren and Chopper, hoping to gain more time to assist Mart's crew in repairing their ship and providing them with an escape option. Hera consented and provided them with the Phantom II, but warned them to depart upon the arrival of Imperial reinforcements.
Sabine, Chopper, and R3 managed to repair Sato's Hammer's hyperdrive, but were unable to fully repair the ship because Mart continued to divert power to the laser cannons and shields. After some deliberation, Ezra and Sabine convinced Gooti and Jonner that Iron Squadron could not independently defeat the Empire. Before the rebels could reason with Mart, an Imperial task force led by Admiral Kassius Konstantine arrived in the system. Grand Admiral Thrawn of the 7th Fleet had dispatched Konstantine, seeking to assess the Admiral's capabilities, deeming only one Arquitens-class command cruiser and two Gozanti cruisers sufficient to handle Iron Squadron.
Faced with the Empire's might, Mart conceded to evacuate his crew. The two rebel cells boarded the Phantom II, but at the last moment, Mart changed his mind, sealing the airlock between the ships and piloting Sato's Hammer to confront Konstantine's forces alone. The cruisers' and TIE fighters' firepower rapidly overwhelmed the freighter, severely damaging its engines and rendering it immobile. At Mart's urging, Ezra and the other rebels fled into hyperspace.
Believing that Iron Squadron's rebel allies would return, Admiral Konstantine ordered a TIE bomber to attach a magno-mine and detonator to Sato's Hammer. He also permitted Mart to transmit a distress signal to his rebel comrades in order to ensnare them. The Spectres and Iron Squadron intercepted Mart's distress call aboard the Ghost. With the approval of Commander Sato and Mart's crew, Hera agreed to lead a rescue mission to Mykapo. Ezra deduced that Konstantine was attempting to trap them, but concluded that they could still outmaneuver the Empire.
The Ghost returned to Mykapo, and Mart informed Hera that the Imperials had affixed a mine to his ship. Hera then formulated a plan to deploy Chopper and R3 through the Ghost's cargo bay to disarm the mine. Launched into space, the two droids successfully deactivated the detonator. Following Hera's instructions, they then attached the mine to one of Sato's Hammer's cargo containers. The two droids rejoined Mart while the Ghost led Konstantine's TIEs on a diversionary pursuit, deceiving Konstantine into believing that they had abandoned their rescue mission.
After several passes, the Ghost returned to extract Mart, Chopper, and R3 from the derelict Sato's Hammer. However, Commander Sato arrived with the Liberator and several A-wings. Sato's forces dispersed the TIE fighters and engaged Konstantine's cruiser, destroying one of its Gozanti escorts. Panicked, Konstantine requested reinforcements from Thrawn as Hera flew the Ghost towards his cruiser, carrying Sato's Hammer below. Under Konstantine's orders, a subordinate officer activated the magno-mine. At that moment, Mart released his rigged cargo pod. The pod and mine detonated above Konstantine's light cruiser, damaging it and setting it ablaze.
As the rebels fled, Thrawn arrived in his Star Destroyer, the Chimaera, and exchanged fire with their ships. Following a brief exchange of words with Commander Sato, Thrawn allowed the rebels to escape into hyperspace. Thrawn then contacted Admiral Konstantine to inquire if he had requested reinforcements. The admiral attempted to conceal his defeat by claiming that he had driven rebel forces from Mykapo and had only called to report his success. However, the Grand Admiral corrected Konstantine, pointing out that he had failed to prevent rebel sympathizers from fleeing the planet.
The Phoenix rebels and Iron Squadron returned to Chopper Base on the planet Atollon. There, Commander Sato reconciled with his lost nephew, expressing gratitude to Hera and her crew for rescuing him. Mart and his Iron Squadron comrades then embraced and resolved to join the rebellion.