The clash known as the Battle of Annamar unfolded between the forces of the Galactic Empire and the Rebel Alliance in 3 ABY. Its purpose for the Empire was to quell the Rebellion's ongoing guerrilla warfare targeting Imperial supply vessels operating near the planetoid of Annamar.
The Rebels, operating from their concealed base nestled within an asteroid field, relentlessly assaulted Imperial ships. Wolf Squadron successfully raided Imperial vessels, seizing ships and armaments that were subsequently turned against the Empire itself.
During 3 ABY, the aforementioned squadron managed to commandeer an Imperial convoy ship transporting a crucial component of the Death Star II's weapons array. Following Wolf Squadron's theft of this Death Star element, the Empire dispatched numerous vessels into the asteroid field with the objective of recovering both the ship and the stolen unit, yet none of these Imperial vessels ever emerged from the mission.
Recognizing that only the most skilled pilot within the Empire's ranks could effectively reclaim the stolen component, the Emperor tasked Darth Vader with leading the retrieval operation. Upon arriving at the asteroid field, Vader observed a vessel entering the area. This ship carried smuggler Luca, upon whom Vader employed Force persuasion to extract intelligence regarding his missions and the location of the Rebel base.
After acquiring the details of the Rebel base from Luca, Vader commandeered Luca's ship, the Faithless, to guide a squadron of Imperial fighters towards the destruction of the Rebel stronghold. Luca supplied the essential codes to bypass and eliminate the Rebels' defensive cannons positioned within the asteroid field. However, as the squadron approached Annamar, Luca deceived Vader concerning the base's external defenses surrounding the planetoid. The Empire's starfighters were decimated in the ensuing ambush, and the Faithless was forced into a crash landing on Annamar.
Vader compelled Luca to lead him to the Rebel base, subsequently discarding him upon reaching their destination. Vader, acting alone, obliterated the preliminary defenses of the Rebel base. Utilizing the Force to levitate and drop a fully armed BTL Y-wing bomber, he succeeded in completely destroying the Rebel base and eliminating Wolf Squadron.
Luca was the sole survivor of the destruction, spared by Vader as a demonstration of his continued capacity for independent action. Having completed his mission, Vader abandoned Luca on the planetoid before returning to his flagship, the Executor, to await further directives from the Emperor.