Raid on Lockup
From Halopedia, the Halo wiki
At some point, a UNSC Army Pelican was shot down in "the Cauldron" and assumed destroyed. However, the Pelican survived intact and was captured by the Covenant who transported it to "Lockup." Tying energy tethers from the Forerunner structure into the dropship's comm systems, the Covenant were able to turn the Pelican into a listening post to spy on the UNSC's communications and anticipate their moves in battle.
During the Assault on Cyclone, Spartan Jared Miller the strange ability of the Covenant to seemingly predict Fireteam Crimson and Fireteam Kodiak's movements, but couldn't determine the source of it though he doubted it was a coincidence. While Crimson was helping Fireteam Lancer attack a Covenant base in the "Warrens," Poker Squad captured a wounded Sangheili who offered up the location of the Covenant listening post in exchange for his life. Palmer ordered Poker to check the intel and make the deal, causing the prisoner to point them to "Lockup."
Destroying the jammers
Fireteam Crimson and a squad of UNSC Marines were deployed to "Lockup" in order to destroy the listening post a captured Sangheili had revealed was located there. A Pelican carrying the UNSC forces eliminated three guarding Unggoy with its guns before depositing the Spartans and Marines to complete their mission.
The UNSC forces were immediately engaged by the Covenant forces defending the landing zone, but managed to eliminate them. Spartan Jared Miller directed Crimson to the door controls to the next area, but got interference around Crimson's uplink which he suspected could be why drones were unreliable in that particular area. Realizing that the Covenant had jammers, Commander Sarah Palmer ordered Miller to have them on the lookout for jammers as well. Crimson fought their way through a hallway defended by Covenant, including a Stealth Sangheili armed with an energy sword and reached a large open area on the other side.
In the heavily-defended area, Miller detected three energy signatures matching known Covenant jammers. Miller directed Crimson to the jammers which they managed to destroy while fighting off the Covenant, including reinforcements deployed from Phantoms, two Wraiths patrolling the area and a third dropped off by a Phantom.
Destruction of the Covenant listening post
After all of the Covenant were eliminated in the area with the jammers, Miller detected a UNSC transponder in the adjacent chamber. Entering the chamber, which was heavily defended by Covenant forces including several Ghosts, Crimson found a UNSC Army Pelican suspended in energy tethers. Miller identified the Pelican as one shot down in "the Cauldron" and assumed destroyed and it was quickly realized that the Pelican was the listening post, its comm systems enabling the Covenant to listen in on UNSC transmissions. Crimson battled the Covenant guarding the captured Pelican, bolstered by reinforcements from Phantoms and heavy orbital insertion pods. Eventually, Crimson managed to eliminate all of the Covenant forces.
After the Covenant were gone, Miller determined that the energy tethers were tied into the Pelican's comm systems and ordered Crimson to break them. As Crimson activated the four consoles around the suspended Pelican that would sever the energy tethers, Phantoms brought in more reinforcements which failed to stop Crimson. Once the link to the comm system was severed, Miller contacted Robert Dalton for a ride out and an orbital strike to destroy the Pelican which Dalton obliged. However, before either could arrive, another Phantom deployed more Covenant troops, including four Hunters. Crimson was able to eliminate all of the Covenant troops and clear a landing zone for extraction.
Once the landing zone was clear, Crimson was extracted by a Pelican. As they flew away, Dalton targeted the captured Pelican with three missiles from orbit, destroying the Pelican and preventing the Covenant from ever using it as a listening post again.
List of appearances