The confrontation known as the Recovery of the Sealion unfolded during the Zaarin insurrection.
Namuura Din, who held the position of commanding officer aboard the Imperial Victory-class Star Destroyer called the Zeplin, secretly provided the Rebel Alliance's MC80 Star Cruiser Link with crucial intelligence concerning the true state of the Death Star II located at Endor, as well as details about the Missile Boat prototype named the Sealion. While the Link and its crew were captured before they could disseminate the information about Endor to the Rebel Alliance, the Sealion had already been dispatched to a Rebel outpost. After inferring from an Imperial scout in the area that the Sealion had remained at the station as no ships had departed since its arrival, Imperial forces arrived to examine the containers for the Sealion. Their objective was to either recover the container or destroy it to prevent the Rebels from tampering with it and uncovering its secrets. Maarek Stele received the assignment to locate the Sealion's container. He piloted the sole Missile Boat remaining on the Imperial-class Star Destroyer Garrett, designated Tau 1. Five TIE/LN starfighters from Delta Squadron provided starfighter support for the operation, while three TIE/IN interceptors and three TIE/Advanced starfighters from Zeta and Eta squadrons, respectively, were held in reserve. Just prior to the operation, the Priest of the Prophets of the Dark Side informed Maarek Steele that Darth Vader had requested confirmation on whether the Rebels had already dismantled the missile boat. Consequently, they stated that they would deploy a craft to board the container and extract the missile boat after Steele identified the container holding the Sealion.
Upon Maarek Stele's departure from the hangar, he aided TIE fighters in engaging and eliminating Z-95 Headhunters and R-41 Starchasers. Shortly thereafter, the Strike Cruiser Piimi appeared and engaged the Imperial-class Star Destroyer Garrett, only to be repelled, possibly destroyed. Stele contributed to the starfighter screen, defending against numerous X-wings, A-wings, B-wings and Y-wings. After addressing the Rebel fighters, he inspected the Class-B containers at Niicee, discovering that each contained warheads until he located the one housing the missing Missile Boat. Subsequently, the Garrett launched the Cargo ferry Omega 1, escorted by Stele, which then boarded the container and retrieved the prototype. Stele proceeded to destroy the container.
After pinpointing the location of the Sealion, the Imperials came to the conclusion that the Rebels had not tampered with it. Nevertheless, due to both the theft and Demetrius Zaarin's act of destroying all Missile Boat manufacturing facilities through bombing, resulting in thousands of deaths, the Emperor Palpatine ordered the recall of all surviving Missile Boats in Imperial possession, placing them in protected storage until further notice. This order was never revoked due to his death at Endor. Partly because of this, and because Grand Admiral Thrawn requested Stele's expertise in the final confrontation with Zaarin at To-phalion Base, Stele was reassigned to the TIE/Advanced Alpha Squadron and dispatched to To-phalion Base to assist Grand Admiral Thrawn in hunting down Zaarin once and for all.
This particular mission is featured in the 1994 PC game Star Wars:TIE Fighter.
The main goal of the mission was the destruction of the Sealion's container. However, a bonus objective could be achieved by waiting a sufficient amount of time after identifying the container to allow the Omega 1 cargo ferry to retrieve the Sealion.
This analysis assumes the completion of both "Primary" and "Secondary" objectives. The "Bonus" objectives include the destruction of the Nebulon-B2 frigate Equator, the XQ4 Platform Enin'sd and the YT-1300 transport Opos.