Infinity sends the Master Chief and Gypsy Company to neutralize the gravity well keeping them on Requiem.

Captain Del Rio surveys Requiem's surface from the window of UNSC Infinity's bridge. Two Broadsword fighters pass overhead, disappearing along the horizon. He gazes around the bridge before walking over to the holodeck. The hologram depicts a Pelican flying through a desert canyon. Del Rio proceeds to address the ground teams.

Andrew Del Rio: Infinity to Gypsy Company.

Meanwhile Gypsy Company's Pelicans, flying through the canyon.

Del Rio (COM): The air corridor to the gravity well is blocked by a network of particle cannons.

Scene transitions to the interior of the Pelican. The Master Chief, Marines, and two SPARTAN-IVs observe a holographic display of Del Rio as he speaks.

Del Rio (COM): Infinity's shields are still down. Open the lane for us to move up and provide air support.
Master Chief: Captain, what's Force Recon's assessment of the terrain?
Del Rio (COM): (annoyed) I know you've been off the field for awhile, Master Chief, but this is a blowthrough op. Sending in recon would just slow us down.

An image of a particle cannon appears next to Del Rio.

Del Rio (COM): Telemetry indicates that the particle cannons are being controlled from a command post southwest of our position. Roll on that target, and neutralize those guns. We'll meet on the other side and take the gravity well. Infinity out.

Del Rio ends the transmission.

Cortana: I don't know about you, but I usually like a little more 'intel' with my intel...
Master Chief: We'll make it work.

The Pelican prepares to land, and John turns to the door as it opens. The Marines and Spartan-IVs form up behind him.

They got onboard the Mammoth as the Pelicans were patrolling. Master Chief grabbed his jetpack as Del Rio com appeared

Del Rio (COM): Gypsy Company, this is Captain Del Rio. The board is green. Let's shut that gravity well so we can go home. Good hunting. Infinity out.

The Mammoth is now on the move. As Pelican almost Target it was a terrible mistake as they were in the kill box They were shot down by the Cannon.

Lasky (COM): Infinity! Pelicans down!
Del Rio (COM): Get to the crash site and retrieve that target designator, Gypsy. You've got no chance of clearing those guns without it.
Lasky (COM): All teams, we've got Covenant squads digging in on the ridgeline. Weapons free, people.

They fired at will at the Covenant Forces as Master Chief manages to retrieve the Target Designator and targets at Phantom then it was shot down and so did Cannon. He went back to mammoth. After neutralizing the covenant and cannons They were ambushed by the Covenant Force. But Master Chief and Marines fought back as they were completely neutralized.

Lasky (COM): Thanks, Chief. It was getting a bit dicey there for a minute.
Lasky (COM): All hands, form up on us.
Del Rio (COM): Lasky, this is Infinity. Status.
Lasky: Mammoth's in pretty bad shape, sir. She'll make it to the objectives as long as nobody starts throwing rocks at us.
Del Rio (COM): Not a chance we can take. I'm sending teams out to pull some of their fire off you so you can make it to the gravity well.
Lasky: Roger that, sir. Gypsy, let's move.
Del Rio (COM): Shadow Company. Castle Company. Put some pressure on those other particle cannons.
Castle Leader (COM): Castle reading five by five. On station, ready to assist.
Shadow Leader (COM): Shadow Actual to Infinity. Encountering enemy air! Significant EOF closer to the emplacements.

The Chief boards the Mammoth, and it begins moving towards the next objective.

The Mammoth reaches a series of waterfalls and comes to a stop.

Lasky (COM): OK folks, terrain's too rough around these tributaries. Assault force, back on the Mammoth. Anyone not on board is getting left behind. All right, sealing her up. Mammoth is mobile.

As the Mammoth begins moving again, the Chief's HUD flickers as Cortana experiences another rampant episode.

Cortana: (voice heavily distorted) They don't care about you - they replaced you!
Cortana: (voice normal) Blast it!
Master Chief: "It's OK."
Cortana: (voice slightly distorted) How? How is this OK? How is putting you at risk because I can't hold it together OK? Chief, do you understand what rampancy is? Really? We don't just 'shut down'. Our cognitive processes begin dividing exponentially according to our total knowledge base. We literally think ourselves to death.
Master Chief: You know I won't let that happen.
Cortana: "And if it happens, anyway?

The Mammoth rounds a corner, coming to a dead end. A small path leads up to a Forerunner structure to the right.

Lasky (COM): 117, Lasky.
Master Chief: Go, Commander.
Lasky (COM): We've got significant blockage up ahead. Think this is about it for the Mammoth.
Cortana: The command post for the particle cannons is through that trench.
Master Chief: Sir, I can move faster alone.
Cortana: We'll see you back on Infinity, Commander.
Lasky (COM): Lasky, out. (displayed, but not spoken)

He got off the mammoth and grabbed his Sniper and shot Covenant Troops then switches his Assault Rife to fire. After he fought his way to Forerunner Structure, he walks through the hallway.

Cortana: This elevator should take us directly to the coordinates Infinity provided. Almost like those Sentinels wanted us to get the particle cannons offline.
Masyer Chief: This could be a trap.
Cortana: You say that like there's a second possibility.

More Sentinels lead the Chief through the lower levels of the facility, taking him to the controls for the particle cannons.

Cortana: We've reached the coordinates. This looks like the place.

The Chief proceeds, plugging Cortana into the console ahead.

Cortana: The particle cannon network must use these arrays for targeting and guidance. It's an automated system so it won't technically allow me to redirect the cannons to fire on one another... Technically.

Cortana shuts the cannons down.

Cortana: Cortana to Infinity. The guns should be offline. How's it look from up there? Infinity?
Master Chief: Cortana-
Cortana: Something's in here- Chief!

Cortana disappears from the console.

Master Chief: Cortana? Cortana!

As the Chief makes his way back the way he came, a hard light bridge appears on his right. The Chief follows a series of tight corridors, arriving to find five Sentinels waiting in front of a door. The door opens as he approaches. A beam of blue light with Cortana standing in it waits on the other side. As he steps into it, the screen washes to white.

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He finally knows the truth about Promethean Knights were humans and manages to receive the Composer Immunity.

The Chief's body is held up by the pillar of light. He glows with energy as the Librarian accelerates his evolution, and is lowered into a crouch. He stands up, and almost immediately he is beset by Promethean forces. Cortana appears on a pedestal to his left.

Cortana: Chief! Up here!

He fought the Knights and retrieved Cortana.

Master Chief: How do we get out of here?
Cortana: Elevator. Back of the chamber.

The Chief heads over to the elevator, boarding and taking it down. Near the elevator is the fourth terminal.

Cortana: Chief, what happened? Your bio-readings are all over the map!
Master Chief: It's a long story, but I know what the Didact's after.
Cortana: I know that part. The Librarian filled me in when she snatched me from the system. But what I don't know is what she did to you!

The elevator comes to a stop, a portal to exit the facility waiting for the Chief. As he steps through it, the Chief is instantly taken to a battlefield outside the gravity well

Marcus Stacker (COM): I'm reading Sierra 117 on-sensor. Everyone form up on the Chief!
Master Chief: "Sierra 117 to Infinity, what's our status?"
Del Rio (COM): "We're taking a beating up here."
Master Chief: Does Infinity have a shot on the gravity well?
Del Rio (COM): Negative. We'll never be able to get a target lock with all the air traffic we're seeing.
Cortana: Captain, what if we can spot the target for you with the laser designator?
Del Rio (COM): Do it! TAC-COM, find the Chief coordinates for somewhere with line of sight!

The Chief fights his way up the hill towards the gravity well.

The convoy destroys the first line of Covenant.

Stacker (COM): First line clear. Check it off. Push forward! All eyes on the Chief. He's lead dog!

The convoy destroys the second line of Covenant.

Stacker (COM): Second line clear. This ain't a picnic. Let's move up!

The Chief comes to a Covenant shield blocking the way to the gravity well.

Cortana: Looks like we're blocked! Chief, head down and find a way to destroy that shield!

Off to the left, the Chief approaches two shielded generators powering the large shield. He destroys the first one.

Cortana: Shield's weakening! Keep it up!

The Chief destroys the second generator.

Cortana: There's a clearing just past this ravine. We can get eyes on the gravity well up there!

The Chief makes his way to the gravity well. As it comes into sight the Chief moves towards the target designator that lies in wait.

Cortana: Infinity, we're at the gravity well.
Del Rio (COM): Then paint that damn target so we can get out of here!
Cortana: You heard him, Chief. Line up the shot.

The Chief picks up the target designator and paints the gravity well.

Del Rio (COM): Target locked! Firing for effect!

Infinity's fired projectile. It hits the gravity well, destroying it with a clean shot. he watches the gravity well explode before walking off to Infinity

Infinity is now in flight. inside the ship, Master Chief, Cortana, Del Rio, Lasky, and Palmer gathered around the holo-table.

Del Rio: Infinity cannot handle that kind of punishment. Not again.
Cortana: This isn't about us or this ship anymore.
Master Chief: Sir, we've seen what the Didact is capable of. If we let him leave this world, humanity will be at risk.
Del Rio: Look. I understand what you think you saw-
Cortana: Think?
Master Chief: With all due respect, sir, I know what I saw.
Del Rio: And with all due respect to you, Soldier, I'm not willing to jeopardize my ship because of the hallucinations of an aging Spartan and his malfunctioning AI.
Lasky: Sir - what if he's right?

Del Rio pauses, giving Lasky a disbelieving look.

Del Rio: Nav - as soon as we know we're airtight, I want a course laid in to Carinae Station. Comm, prepare a warning beacon. The ship's lights grow brighter. Del Rio and Lasky look up and then to Cortana as her body flickers red with anger.

Cortana: (enraged) I will not allow you to... leave! This! Planet!

A wave of energy expands from Cortana as she screams at Del Rio, causing displays to short out and spark. Almost instantly, she returns to her normal state, showing embarrassment for her rampancy's progress as the holo-table sparks and smokes.

Master Chief: (concerned) Cortana...
Cortana: I didn't mean to... I didn't mean to do that...
Del Rio: Commander Lasky. Pursuant to Article 55 of UNSC Regulation 12-145-72, I am ordering you to remove that AI's data chip and retire it for final dispensation.
Cortana: Don't... Please... please. I don't want to... You don't want me to... please.
Del Rio: (impatiently) Remove the chip now, Commander.
Cortana: Please... I don't want to...

Lasky reluctantly reaches for the chip. However, the Master Chief takes it before he is able. As Cortana disappears from the table, Del Rio advances on the Chief.

Del Rio: Give. Me. That. Chip.
The Chief defiantly inserts Cortana's chip into his helmet.

Master Chief: The Didact has to be stopped. If you won't do that... I will.
Del Rio: (angrily) I am ordering you... to surrender that AI!

The Master Chief steps forward, towering over the captain.

Master Chief: No, sir.

Del Rio furiously stands back and turns to his bridge crew members, pointing to the Chief.

Del Rio: Lieutenant! Arrest that man!

Palmer and other personnel don't move. Lasky tries to diffuse the situation.

Lasky: Captain...
Del Rio: ARESST HIM!!!
Lasky: Captain!

Master Chief looks at Lasky.

Master Chief: Get word back to Earth that trouble is coming. Cortana and I will do what we can from here.

Lasky nods. The Chief leaves the deck. Del Rio turns to watch him go, a look of disbelief and anger on his face.

Officer: Ohhh. Burn.
Officer: Ah Shut Up.