From Halopedia, the Halo wiki
Raven Down is the fifth mission of Halo: Fireteam Raven.
Having extracted from the ice canyons, Fireteam Raven's UH-144 Falcon is shot down. The ODSTs fight through hordes of Flood into a nearby Forerunner structure, ultimately making it to an escape. The team make a beeline for the crash site of the Pillar of Autumn.
Having been hit by plasmafire in the previous mission, Fireteam Raven's UH-144 Falcon has crash-landed on an unknown part of Installation 04. The mission opens with the team's Falcon now on fire, and losing altitude.
The Falcon crashes into the ground amidst a pack of Flood combat forms. The Falcon skids along the ground several metres. Fireteam Raven equip their MA5B assault rifles and immediately get to work fighting off Flood inside the downed craft. Several plasma blasts rock the ground as three Type-26 Banshees enter the battle from behind. As Fireteam Raven escapes the Falcon, the wreckage is overrun with Pod infectors, followed by Flood tank forms. As Raven begin fighting more combat forms, several Covenant Sangheili can be seen fighting in the distance. Overhead, a Ru'swum-pattern Phantom, crawling with Flood forms grappling the exterior, explodes with its wreckage crashing in front of Raven. Several Suicide Unggoy ambush the team from the right, revealing a Covenant squad of Sangheili, Kig-Yar and Unggoy guarding the entrance to a Forerunner structure. The aliens are dispatched quickly.
As Wellsley finishes talking, several Banshees begin attacking, turning Raven around to find yet more Combat forms attacking. Raven retreat into the structure to find more Covenant infantry waiting for them, including several energy sword-equipped Sangheili. Raven pick up a Type-33 needler recovered off a Grunt's corpse, and begin ascending to the next level of the structure. Entering the next room, more Covenant wait. Turning around, a large ramp exits out onto an exterior balcony, with Unggoy troops pushing down. As Fireteam Raven begin going up the ramp, Pod infectors swarm into the room from below. Exiting out onto the balcony, Raven find them face-to-face with two Sangheili. Before they can engage, however, a new threat emerges; several massive tentacles impale the Elites from below the platform, before two hulking Flood Juggernauts climb onto the balcony. One of the juggernaughts throws the Sangheili it had impaled off the balcony. The Juggernaughts are killed, and the Pelican flies past. Fireteam Raven mount nearby Type-26 Shade turrets and begin defending the Pelican from oncoming Banshees. Raven exit the turrets when Pod infectors begin swarming the platform, however, and switch back to their Assault Rifles. Fireteam Raven ascend another ramp while pursuded by infectors and combat forms, before encountering two tank forms, and some Flood carrier forms. The squad encounter another group of elites led by an Ultra, before two Hunters jump up onto the platform.
Raven man the Shade Turrets once again to fend off more Banshees and eventually two Phantoms. One of the Phantoms drops a Okarda'phaa-pattern plasma rifle, which is picked up by the group before they proceed into a hangar bay with several Sangheili and parked Banshees. Yanme'e swarm into the room, while Flood also begin to engage Covenant. One of the Banshees attempts to take off with two Combat forms grappling the outside, resulting in the Banshee's death. Raven retreat into a side corridor, and out onto a Forerunner landing pad. Two Hunters, two juggernaughts and two tank forms can be seen battling. The tank forms engage Raven, while the two juggernaughts pick up the hunters and beat them into the ground before throwing them off the ledge to engage the humans. They are killed and the Pelican arrives at the landing pad, with a horde of Flood spilling out of the corridor onto the platform.
Raven retreat onto the Pelican while firing their assault rifles. Ava Lang throws a grenade which kills many of the Flood, buying time for the dropship to take off. Flood combat forms attempt to jump onto the ship but only fall off the platform.