Following the Alicorn's gambit to obtain nuclear shells at Anchorhead, the Erusean military transmitted the specs of the super-sub to the Oseans, revealing that the sub had a powerful rail cannon on board that could be used to attack Oured. David North relayed this information to the Long Range Strategic Strike Group. David also correctly deduced that the submarine would launch its nukes on September 19th, due to celebrations being held on Oured to commemorate the end of the Usean Continental War
Knowing this, David narrowed the Alicorn's possible routes by comparing routes through Osea and its allies' underwater sound surveillance networks and routes feasible to get to firing range by the 19th. David once again correctly surmised that the Alicorn's only possible route was to move along the Azalea Seamount chain, an underwater mountain range. By the 14th, it would arrive in an area of the Spring Sea known as PX80443. However, if it got much further, it would arrive at the Peony Trench, a deep abyss where the sub could feasibly reach its max operating depth of 600 meters, far too deep for any attack to reach it.
As the operation began, Specter Squadron began to drop the sonobuoys across the area of operations, however multiple SLUAVs and aircraft operated by the Alicorn's air wing were deployed to prevent the LRSSG and the ASW craft from finding the Alicorn. As they engaged the Alicorn's aircraft, David contacted them, informing them of a scuffle between two groups of demonstrators, noting that there were advertising drones flying above the crowd. Once the ASW craft deployed all their sonobuoys, Trigger activated the MAD within the search area. As they centered in on its actual location, the Alicorn deployed special jammers mounted on buoys that interfered with the MAD's signal transmission, forcing the LRSSG to destroy the buoys. However, the jamming buoys generated huge underwater explosions once destroyed, providing ample underwater noise for the Alicorn to use as cover while making a break for the Peony Trench. Once the jammers were destroyed, Trigger once again located the Alicorn, and the naval fleet launched anti-submarine missiles, damaging the Alicorn's ballast tanks and forcing it to surface.
As it surfaced, the Alicorn activated all its anti-aircraft weapons and railguns, and fired directly at the naval fleet, heavily damaging and sinking the majority of the deployed ships, engaging the LRSSG. To prevent any further damage, the Alicorn deployed special barrier drones, which utilized a small electromagnetic barrier similar to the Arsenal Bird's APS, preventing a majority of attacks from the LRSSG from connecting with the sub. As the LRSSG continued to attack, David contacted them once more, informing them that he had realized that the advertising drones were secretly providing terminal guidance for the Alicorn. He proceeded to make a call to the nearest Osean Air Force base, requesting they jam the entire airspace with their electronic warfare aircraft. Trigger attacked the Alicorn's ballast tanks, preventing it from being able to submerge. With the Alicorn no longer able to submerge and heavily damaged, Captain Torres attempted one last resort.
Torres broadcasted on an open channel to the Osean forces announcing that he and his crew would surrender. Under international law, this would prevent an attack on the sub. David opened communications with Torres, informing him that they had jammed his terminal guidance system, and that his shot would miss. Torres, in turn, told David of his days with the Erusean navy, telling him a story of when he hit an enemy ship 30 kilometers away in the middle of a storm. Torres then launched barrier drones between him and the Oseans, and proceeded to deploy the Alicorn's rail cannon, revealing his true colors. Disobeying orders from AWACS Long Caster, Trigger wove through the barrier drone swarm and managed to strike the barrel of the rail cannon, adjusting its firing angle by just a few degrees, causing it to miss the target.
Furious, Torres ordered the crew to reload the rail cannon and fire again. In a final assault under direct orders from Wiseman, the LRSSG attacked the Alicorn, whose crew was making a defiant last stand with all remaining weaponry. With the Alicorn's fire control systems damaged and unable to manually raise the elevation of the rail cannon barrel, Torres ordered the flooding of the aft trim tanks, causing the boat to sink aft first, however this would also give the cannon the elevation it needed to hit home. Before the cannon could be fired, however, Trigger destroyed the base of the rail cannon, causing a chain reaction that created multiple explosions across the magazines of the weapon emplacements. This ultimately culminated in a massive explosion amidships, breaking the sub's hull in two. The Alicorn sank with all hands lost before detonating in a massive explosion, sending a massive geyser of water high into the sky.
32 hours after the battle,, the two squadrons set off for Cape Rainy as part of a mission to capture an Erusean air base. Meanwhile, David North uploaded the data he had gathered on Trigger's flight style to Alex, and the AI realized a curious element of the operations Trigger took part in; the percentage of surviving allies remained high whenever Trigger was present, while decreasing severely when he was not. This information convinced North to write a report in favor of Trigger to the Osean president regarding the Alicorn operations.