Floodgate

"Floodgate" is the sixth campaign level of Halo 3 and the first Halo 3 level in which the Flood appears.

Upon completing the level on Normal, Heroic, or Legendary difficulties, the player will earn the "Cleansing" achievement and 30 Gamerscore; in Halo: The Master Chief Collection, this achievement, now only worth 10 Gamerscore, can also be obtained on Easy. Earning over 15,000 points in the Campaign meta-game will give the player the Exterminator achievement and 10 Gamerscore.

Background
It takes place in Voi, Kenya on the continent of Africa on Earth during the Battle for Earth. Floodgate is the first campaign mission where Sangheili allies other than the Arbiter, Thel 'Vadam, are encountered in Halo 3. It is also one of the shortest levels in the game.

Shortly after John-117 disables the Covenant anti-aircraft battery in the previous level, The Storm, UNSC frigates under the command of Admiral Hood attacked the Covenant-controlled Forerunner Dreadnought. This attempt failed, as the Dreadnought survived unscathed. The Prophet of Truth then activated a Portal to the Ark and his Dreadnought entered the slipspace rift, followed by the rest of the Covenant fleet. Immediately afterward, a Flood-infested battlecruiser emerged from slipspace and crashed into Traxus Factory Complex 09.

In order to eliminate the infestation, John-117 and Arbiter Thel 'Vadam must overload the crashed cruiser's engines, wiping out the entire city and the Flood with it. To do this, they push back through the factory where they just came from, fighting many Flood combat forms and pure forms, the next stage in Flood evolution. They are then aided by the arrival of Rtas 'Vadum and a Sangheili fleet. 'Vadam and John, along with a Sangheili strike team, push forward to the crashed ship, and 'Vadam holds position while John extracts what is believed to be Cortana, stored in a Covenant storage device. This eventually turns out to be only a recording. Inside the crashed Flood ship, John-117 has an unexpected reunion with 343 Guilty Spark. Though distrustful of the monitor's intentions, John accepts Guilty Spark's offer of aid. After the area is evacuated, Sangheili warships begin to glass Voi and the immediate vicinity to prevent further contamination by the Flood.

Onboard Rtas 'Vadum's, Shadow of Intent, Guilty Spark extracts Cortana's recorded message from the storage device. The recording reveals the existence of a solution to the Flood on the other side of the Portal without firing the remaining Halo rings. The Master Chief convinces Lord Hood to allow an expedition through the Portal to find both Truth and Cortana's solution. A joint human-Sangheili fleet then heads into the Portal.

It Followed Me Home
'Hot zone. Weapons free.'

{Gameplay}

''Fade in outside the city. The Chief and 'Vadam are standing under the remains of the Covenant AA gun. The sky is choking with thick smog from the crashed cruiser. Faint screeching and growling noises can be heard in the distance.''


 * Commander Miranda Keyes (COM): "The Flood - it's spreading, all over the city."


 * Lord Hood (COM): "How do we contain it?"


 * Commander Keyes (COM): "Find the crashed Flood ship; overload its engine core. We either destroy this city, or risk losing the entire planet."


 * Lord Hood (COM): "Do it."


 * Commander Keyes (COM): "Chief, make your way to the crash site."

''To the right, two Marines are seen on a cliff edge, fighting off several Flood combat forms. They are overrun and typically mutate into more combat forms.''

The Chief and Thel 'Vadam reenter the city.


 * Gunnery Sergeant Reynolds (COM): "All squads, report!"

At this time, a group of Flood combat forms jump from the building on the right.


 * Marine (COM): "Multiple contacts, unknown hostiles."

Flood screeches are heard.


 * Thel 'Vadam: "There are some powerful weapons we've not yet used..."


 * Marine (COM): "There! Over there! We're surrounded, Sergeant!"

The Chief finds a Marine squad on a loading ramp.


 * Marine (COM): "Aaaaah!"


 * Reynolds (COM): "Fall back, fall back!"


 * Female Marine: "Sergeant, come on!"

Pod infectors and combat forms (all former humans and Jiralhanae) descend from above and swarm on the Marines at the ramp, killing, then infecting them, forcing the remaining Marines, the Chief, and 'Vadam to kill them.


 * Reynolds: "Ahhh!"

The Sergeant becomes mutated by a Pod infector.


 * Reynolds: "No! No! No!"

A Marine proceeds to attack the reanimated Sergeant.


 * Female Marine: "What are you doing?! That's the sergeant!"


 * Marine: "That was the sergeant! It ain't no more..."

They fight off the wave of Flood.


 * Thel 'Vadam: "Quickly! Let us find their ship. Make short work of this abomination!"

The Marines accompany the Chief and 'Vadam into a building, where a lone Marine is running away from a horde of Pod infectors.


 * Marine: "Uhh! Get off me!"

or


 * Marine: "Get it off! Get it off!"

''If the Marine is not saved, the Pod infector dives into his chest, gruesomely transforming him into a Flood combat form. This forces the Master Chief and 'Vadam to kill him immediately.''

''Marines led by Gunnery Sergeant Stacker are pinned down behind sandbags by a massive horde of Flood. The Chief and 'Vadam engage and destroy the Flood forms in this section of the warehouse.''

If the Marines are saved from being killed or infected:


 * Female Marine: "It gets inside you, chews you up."


 * Marine: "We gotta get outta here."

''The Chief, 'Vadam, and the surviving Marines head into the next section of the warehouse. Upstairs, two Marines, one wielding a flamethrower, try to combat the Flood as well, but they soon fall to the parasite's overwhelming numbers.''


 * Thel 'Vadam: "Wretched/Accursed parasite! Rise up and I will kill you! Again and again!"

''Reaching the other end of the warehouse, the surviving Marines hold position after clearing the area. The Chief and 'Vadam head upstairs onto an upper balcony, optionally picking up the abandoned Flamethrower for use against the Flood.''

Proceeding forward, the two find a hole in the floor and drop down it, arriving in the office areas.


 * Cortana (Cortana Moment): "Chief! (connection drops) I can't tell you everything...it's not safe. The Gravemind...it knows I'm in the sys-(connection drops)."

''The Chief and 'Vadam force their way through another wave of Flood, and find a Marine huddling in a corner of the large room previously used as an Aid Station, surrounded by three dead Marines. The Marine is holding a pistol, and will occasionally aim it at his own head, before lowering it and burying his face in his hands.''


 * Traumatized Marine: "I...I didn't have a choice...! The L.T...the Sergeant...they were all infected! I could see it crawling...sliding around beneath their skin! (sobs) A-and then they got up...they s-started to talk! Oh, God! Their voices! Oh, God! No, make them stop! I did them a favor...y-yeah that's it; I helped them! (sobs) Maybe...maybe I need to help myself... (breaks out into sobs)"

With no time to spare, the Chief and 'Vadam continue on ahead to the lake bed.

The Master Chief and Thel 'Vadam enter the lake bed of Voi where the Scarab was previously fought and destroyed.


 * Shipmaster Rtas 'Vadum (COM): "Hail, humans, and take heed."

Shadow of Intent
The Flood has Evolved.

{Cutscene}


 * Rtas 'Vadum (COM): "This is the carrier Shadow of Intent."

The Chief and 'Vadam pause to see three Sangheili-controlled s fly in formation as a slices overhead from slipspace.


 * Rtas 'Vadum (COM): "Clear this sector, while we deal with the Flood."

A Sangheili Major and four Special Operations Sangheili leap out of landed Orbital Insertion Pods ahead of the Chief and 'Vadam, and join the battle against the Flood.

{Gameplay}

The Chief and 'Vadam make their way to the Sangheili lance.


 * Thel 'Vadam: "My brothers, I fear you bring bad news."


 * Sangheili Major: "High Charity has fallen, become a dreaded hive!"


 * Thel 'Vadam: "And the fleet? Has quarantine been broken?"


 * Sangheili Major: "A single ship broke through our line, and we gave chase."


 * Thel 'Vadam: "But we had a fleet of hundreds!"


 * Sangheili Major: "Alas brother, the Flood... It has evolved!"

''The Chief, 'Vadam, and the Sangheili fight their way through a massive wave of Flood, including a pair of carrier forms and enter a warehouse. They clear the building of Flood.''


 * Commander Keyes (COM): "Chief, the Elites are looking for something. We didn't believe them when they told us."


 * Sergeant Johnson (COM): "It's Cortana, Chief! She's on that ship! Find her - get her out!"

''The group exits the warehouse. Outside, two Sangheili Phantoms arrive and drop off more Sangheili reinforcements to combat the Flood.''


 * Sangheili Major or Special Operations Sangheili: "Hurry, Demon! We seek the same prize. But our Shipmaster will sacrifice all to stop the Flood."

''The Master Chief, 'Vadam, and the remaining Sangheili head towards the crash site. Along the way, they encounter Flood pure forms for the first time.''


 * Special Operations Sangheili: "What great horror is this?!"

or


 * Special Operations Sangheili: "What is this?! Some abomination from the ancient texts?!"

''The group fights past dozens of pure forms, combat forms (including former Sangheili), and pod infectors before finally reaching the massive, burning hulk of the crashed Flood battlecruiser. Up an incline, an ominous hole resides in the ship's hull, leading to the interior.''


 * Thel 'Vadam: "I shall remain here. We will let nothing pass."

The Chief drops in alone.

Infinite Devil Machine
The Chief drops into a tunnel.


 * Gravemind (Gravemind Moment): "Do not be afraid. I am peace... I am salvation."

The Chief reaches a large room after passing several dead Sangheili Ultras.


 * Gravemind (Gravemind Moment): "I am a timeless chorus. Join your voice with mine, and sing victory... everlasting!"

{Cutscene}

Inside the central chamber of the Flood-infested crashed cruiser, the Chief finds Cortana in a small Covenant hand held memory unit.


 * Cortana (recorded): "Chief!"


 * Master Chief Petty Officer John-117: "Cortana?"


 * Cortana (recorded): "High Charity, the Prophets' holy city, is on its way-"

Cortana's projection above the holographic unit flickers and then disappears.


 * John-117: "Cortana!"

''Suddenly, the humming of a Phantom's gravity drives are heard, and a Phantom appears over the open chamber. Uncertain of its intentions, the Chief turns and aims his assault rifle at it. 343 Guilty Spark floats down from the Phantom.''


 * 343 Guilty Spark: (surprised) "Reclaimer!"

''A Flood combat form appears to the right behind the Chief, and 343 Guilty Spark casually turns and uses a powerful energy beam to destroy it in a single glancing hit. Spark turns back to the Covenant device and begins to interface it with a beam projected from his central eye.''


 * 343 Guilty Spark: "I must act quickly before your construct suffers any further trauma!"

The Chief grabs 343 Guilty Spark and pulls him away from Cortana's storage unit, disabling the interface beam.


 * John-117: "Wait. Leave her alone."


 * 343 Guilty Spark: "If we do not take this device to a safe location, somewhere I can make repairs..."

''343 Guilty Spark continues trying to project his energy beam into Cortana's storage unit. John again pulls him away, disrupting the beam. He then lets go of Spark and confronts him.''


 * John-117: (accusingly) "On Halo, you tried to kill Cortana. You tried to kill me."


 * 343 Guilty Spark: (defensively) "Protocol dictated my response! She had the Activation Index and you were going to destroy my installation. You did destroy my installation. Now, I only have one function: to help you, Reclaimer. As I always should have done."

''The Master Chief stares wordlessly at 343 Guilty Spark, then holds up Cortana's storage device. 343 Guilty Spark takes Cortana's device away, shooting his beam into it while the Phantom projects a gravity lift. 343 Guilty Spark enters it first and the Master Chief reluctantly follows.''

''The view cuts to an aerial one over the whole town of Voi at a high altitude. Although clouds obscure the surface, part of the Indulgence of Conviction is still visible. The Phantom flies away from the ship while two battlecruisers of the Fleet of Retribution glass Voi with their energy projectors.''

''The view then cuts to an aerial one above the Forerunner Portal. Its 'fins' are open and blue energy streams from their tips to the open slipspace portal drifting ominously above the construct. Fighting on Earth has ceased and the Battle for Earth has ended with the departure of the Prophet of Truth's fleet through the Portal hours earlier. Four vessels of the Sangheili fleet are gathered above the Portal and 343 Guilty Spark's Phantom arches to the largest of them: the assault carrier Shadow of Intent.''

Inside the bridge of the Shadow of Intent'', Sangheili and humans are gathered around a long holographic table, with Shipmaster Rtas 'Vadum floating on a gravity throne at one end with his Sangheili attendants, Master Chief and Arbiter Thel 'Vadam in the middle, and Fleet Admiral Hood and Commander Miranda Keyes at the far side of the table. All are silent except 343 Guilty Spark, who is bobbing at the center of the table and interfacing with Cortana's memory unit with his projector beam.''


 * Rtas 'Vadum: "Will it live, Oracle? Can it be saved?"


 * 343 Guilty Spark: "Uncertain. This storage device has suffered considerable trauma. Its matrices are... highly unstable."

343 Guilty Spark glances at 'Vadum and Lord Hood


 * Lord Hood: "Perhaps one of our technicians-"


 * Rtas 'Vadum: (sternly) "That will not be necessary."

As Spark finishes his work, the storage device lights up, and a holographic projection of Cortana springs up.


 * Cortana (Recording): "Chief!"


 * 343 Guilty Spark: "Success!"


 * Cortana (Recording): "High Charity, the Prophets' holy city, is on its way to Earth. With an army of Flood. I can't tell you everything. It's not safe. The Gravemind... it knows I'm in the system."

''Cortana's image flickers and stalls. The Chief turns to Rtas 'Vadum.''


 * John-117: (disappointed) "It's just a message."


 * Rtas 'Vadum: "Let it play."

343 Guilty Spark jolts the device with another beam.


 * Cortana (Recording): "But it doesn't know about the Portal, where it leads. On the other side, there's a solution. A way to stop the Flood, without firing the remaining Halo rings-"

''Suddenly, Cortana's skin lights up. She clutches her head, gasps in sudden pain and collapses onto the "floor".''


 * Cortana (Recording): (softly, her voice filled with agony) "Hurry, Chief... the Ark... there isn't much time."

Cortana's recording ends and she is left staring with desperation at the Chief.


 * 343 Guilty Spark: "I'm... sorry."


 * Rtas 'Vadum: "No matter, Oracle. We've heard enough. Our fight is through the Portal, with the Brutes and the bastard Truth!"

 Sangheili around the room raise their forearms and roar in agreement.


 * Lord Hood: (wearily) "Fine. We'll remain here. Hold out as long as we can."


 * Rtas 'Vadum: "Did you not hear? Your world is doomed." (descends from his seat) "A Flood army, a Gravemind, has you in its sights! You barely survived a small contamination!"


 * Lord Hood: (angrily) "And you, Shipmaster, just glassed half a continent! Maybe the Flood isn't all I should be worried about..."


 * Rtas 'Vadum: (just as angrily) "One single Flood spore can destroy a species. Were it not for the Arbiter's counsel, I would have glassed your entire planet!"

Lord Hood angrily raises his fist at 'Vadum, but Miranda Keyes interrupts.


 * Commander Keyes: "Sir, with respect, Cortana has a solution."


 * Lord Hood: "Cortana? Did you see her condition? How damaged she is?"

While Hood and Keyes argue, the Master Chief bends down and observes Cortana's pained, frozen figure, still collapsed on the holographic table.


 * Lord Hood: "She could be corrupted for all we know. Her "solution" could be a Flood trap!"


 * Commander Keyes: "We should go through the Portal, find out for sure."


 * Lord Hood: "What we should do Commander, is understand - clearly - that this is humanity's final stand - here - at Earth. We go, we risk everything; every last man, woman and child. If we stand our ground, we might just have a chance."


 * Thel 'Vadam: (flatly) "No. If your construct is wrong, then the Flood has already won."


 * John-117: "I'll find Cortana's solution. And I'll bring it back."


 * Lord Hood: "Earth... is all we have left. You trust Cortana that much?"


 * John-117: "Sir. Yes, sir."


 * Lord Hood: "This is either the best decision you've ever made or the worst. Hell of it is, Chief? I doubt I'll live long enough to find out which."

Lord Hood turns, looks wordlessly at Miranda Keyes, and then exits the bridge.

Inside the Shadow of Intent's'' hangar bay, both the Sangheili and the UNSC are getting ready for battle. While a pair of Sangheili Phantoms drift into the hangar on the far side, two Sangheili Banshees glide past in the opposite direction. On the ground, two Warthogs race to the 's loading bay, drawing near a group of Marines clustered around some UNSC crates. At uneasy rest opposing the Marines are a Sangheili Major sitting on a Ghost, along with a few Special Operations Sangheili. The Major's particle beam rifle is resting next to the Ghost. Sergeant Johnson, with his arm full of "stolen" Covenant carbines brushes past the wordless Sangheili, stopping only to scoop up the Major's rifle. The Sangheili, resentful at this non-permitted collection, rise challengingly around Johnson. Johnson ignores them and continues walking.''

''Nearby, a pair of ODSTs are joking with each other when the Arbiter passes by with an acquired rocket launcher over his shoulder and a flamethrower in his left hand. The ODSTs and a pair of nearby Marines watch the Arbiter in awe, when 343 Guilty Spark drifts through the Marines in tow behind 'Vadam, pausing momentarily to glance at one Marine, leaving him speechless. Johnson rejoins the Marines, and begins to hand out carbines.''

''The scene cuts to the fore of the hangar, where a Pelican dropship lays before the hangar's energy field. The Forward Unto Dawn is stationed nearby. The Chief and Miranda Keyes stand at attention before Lord Hood, who looks at them grimly from the rear of the Pelican as the troop bay door shuts and the Pelican takes off. Keyes glances at the Chief wordlessly, and the two leave, going off to their own business.''

Hood's Pelican arcs away from the gathered Sangheili fleet as the Shadow of Intent powers its engines and thrusts into the Portal, followed by the rest of the fleet.

Fades to black.

Level ends.

Glitches

 * The Elite Helmet Glitch occurs on this level. Occasionally, the Elites on the crashed battlecruiser have the face of R'tas 'Vadum.
 * Occasionally, when the player shoots the Pod infector off the Marine in the first building, he will still turn into a Combat Form regardless.

Easter Eggs

 * The Missing Person Poster can be seen in this level.
 * The Fog Skull is found on this level.

Miscellaneous

 * This was the first and only known time the Flood have been on Earth. It also is the first mission in which no live Covenant Loyalists are encountered.
 * This is the first mission where the Flood Pure Forms are introduced
 * This level does not have a carry-on stats from the previous level, The Storm, meaning that the player will start out with a Battle Rifle and an Assault Rifle, no matter what weapons the player had from the previous level. Additionally, any surviving Voi factory workers and Marines that helped the player take down the Covenant AA will not appear, despite appearing in the cutscenes before this mission starts.
 * The Marine with the Flamethrower is actually two-dimensional and has no scripted actions other than two shots and its death animation. However, the corpse can be infected, becoming a normal Combat Form with the Flamethrower.
 * At the first checkpoint, the Marine on the radio that says, "We're surrounded, Sergeant!" is in fact Gus Sorola, the voice actor of Private Simmons from the web series, Red vs Blue.
 * The Sangheili Ultras in the ship can be meleed down the hole and get infected by the Flood.
 * This level and The Covenant are the only levels in Halo 3 to have Sangheili allies besides Thel 'Vadam.
 * It also marks the only time in the game that Special Operations Sangheili fight alongside the player, and the only time in the original trilogy where they fight alongside the Master Chief. As they are the only Elites to throw grenades in the trilogy, they are effective grenadiers, especially in their first engagement with the Flood. However, if you wish for them to survive the level, the Catch Skull is ill-advised, as they will throw grenades with reckless abandon and wind up accidentally sticking an ally or you.
 * With the Mythic Skull turned on, it is possible to stick an allied Sangheili and take their plasma sword without killing him, but it must be done quickly as they will eventually switch back to their other weapon. However, this can only be done with the plasma grenade on co-op, as the Master Chief cannot collect plasma grenades in single-player, unless he betrays an Elite ally.
 * Curiously, only one Spec-Ops Elite will drop via pod in co-op, instead of the usual four. The other Spec-Ops units will later be dropped in by separatist Phantom if one of them dies between then and their introduction.
 * This is the first level in Halo 3 where you can easily get an Energy Sword by default, either betraying an Elite ally (as stating above), or looking near the elevator shaft where the Elites first appear and see a fully charged sword next to 2 Plasma Rifles.
 * Interestingly, the Arbiter does not use either of his acquired weapons in co-op. The flamethrower is used in single player campaign while the rocket launcher is never seen at all. It's possible that both sides are just unofficially sharing supplies so as to better arm themselves.
 * On rare occasions, the lights in the room with the Suicidal Marine may be turned on instead of off.
 * At the end of the factory area it is possible to push any surviving Marines up the stairs where the Flamethrower is. If pushed far enough they will eventually walk the rest of the way and accompany you for the rest of the level up until you enter the ruined Flood ship