This article is about the campaign level. For the Spartan-IV team, see Fireteam Osiris.

Next:	Blue Team
Osiris
Game:	Halo 5: Guardians
Player:	Jameson Locke (Fireteam Osiris)
Date:	October 2558
Location:	Kamchatka
Objective(s):	Rescue Dr. Catherine Halsey
	Halopedia has a walkthrough guide to this level, Osiris (level). See Osiris (level)/Walkthrough.

“

Fireteam Osiris is dispatched to recover the UNSC's most wanted criminal: Doctor Catherine Elizabeth Halsey.

”

Osiris is the first campaign level of Halo 5: Guardians.

Completing the level grants the player the achievement "Into the Fire". During the level, commanding other members of Fireteam Osiris grants the player the achievement "Your Team is Your Weapon". Assisting the Sangheili Warrior with charging the hill on Heroic difficulty rewards the player with the achievement "Enemy of my Enemy".

Transcript

{Cutscene}

Fade in to an ONI facility. Dr. Catherine Halsey walks down a walkway in the middle of a dark circular room, lined by tall black monoliths. Reaching its end, Halsey places her left hand on a scanning panel and the door opens to let her into her lab. Inside, Debussy's Prelude No.4 is softly playing. As she passes her desk, Halsey sets her journal on it. The desk is adorned with books, ONI paper files, an active holoscreen, and a framed photo of Miranda Keyes. Nearby is a hologram of a human brain.

Halsey reaches into the wall and pulls out an armored matrix. She then heads to the far end at the lab, where there is a glowing blue holotank.

• Halsey: (voiceover) Spartan Locke.

Halsey plugs the armored matrix into the holotank. Standing on it is a projection of a blue woman, Cortana.

• Halsey: (voiceover) I have spent enough years with ONI to know the truth.

Halsey smiles at her AI and Cortana smiles back.

• Halsey: (voiceover) Once this is over, after all I have done...

Halsey turns the handle of the matrix in the tank. Cortana's hologram vanishes as she's transferred to its chip.

• Halsey: (voiceover) They'll order you...

The room darkens and Halsey's smile fades.

• Halsey: (voiceover) ...to kill us both.

Cut to black

{Cutscene}

Fade in to Jameson Locke's helmet, lying on a seat inside a Pelican's troop bay.

Cut to the Microsoft Studios logo.

A rotating cylindrical holotank lowers from the ceiling. It activates, displaying several holographic photos of destruction on several human colonies.

Cut to the 343 Industries logo.

Lasky briefs Fireteam Osiris.

Cut to the Pelican bay. Members of Fireteam Osiris are looking at the holotank. An additional screen appears on it as Thomas Lasky begins his transmission.

• Thomas Lasky (Video COM): "Fireteam Osiris. Over the last 72 hours, five colonies have experienced identical events. Massive destruction, Forerunner in origin."

Olympia Vale stands up. A 3D portrait of Catherine Halsey appears on the holotank.

• Lasky (Video COM): "Dr. Catherine Elizabeth Halsey has managed to contact us."

Edward Buck scratches his chin.

• Lasky (Video COM): "She claims to have information on these attacks."

Holly Tanaka passes an M6H magnum to Vale as they look at the holotank. Another screen appears on it as Sarah Palmer joins in.

• Sarah Palmer (Video COM): "Halsey is currently in Covenant custody on the surface of Kamchatka."

Locke stands up as the holotank shows battle plans for Kamchatka.

• Palmer (Video COM): "Your mission is to insert behind enemy lines, retrieve Halsey and bring her back to UNSC Infinity."

The hologram of the Kamchatkan mountain ranges disappears, and a Sangheili hologram replaces it.

• Palmer (Video COM): "Be advised. Dr. Halsey is accompanied by Covenant supreme leader Jul 'Mdama. If you have the opportunity…"

• Locke: "Understood, Commander."

• Lasky (Video COM): "Good luck, Spartan Locke. Infinity out."

The holotank shuts down.

• Locke: "Tracking gear online?"

Vale activates her Artemis Tracking System.

• Olympia Vale: "Affirmative."

Tanaka grabs her helmet from the overhead compartment and approaches the center of the Pelican.

• Holly Tanaka: "Say, before we make this jump, anybody want to say a few words?"

Buck stands and picks up his M45 shotgun, cocking it and holstering it on his back.

• Edward Buck: "I figure if God can hear how scared I am, so can everyone else. Locke, you buying the first drink when we're done?"

• Locke: "You ask, you buy."

Buck chuckles. Locke turns to the others.

• Locke: "Fireteam Osiris, the light is green."

Locke turns around and opens the troop bay door. Vale and Tanaka put on their helmets and jump. Buck smiles and passes Locke his helmet before putting on his own helmet and jumping off the Pelican. Locke puts on his helmet, turns around, and jumps. He joins the others in the sky. Cut to black:

Fireteam Osiris descends into battle.

Open to the four Spartans in free fall. Covenant starships are massed beneath, engaged in battle. The Spartans zoom through the fleet, passing enormous corvettes, carriers and other warships, aiming for the mountain range below.

• Locke (COM): "Comms check."

Tanaka crashes into a Banshee, which explodes near Buck. He narrowly dodges the explosion while Tanaka's energy shields flicker and recharge.

• Tanaka (COM): "Comms working fine, Locke."

• Locke (COM): "Copy that, Tanaka."

A Forerunner mountain platform is shot down and shatters.

• Buck (COM): "Spartan Buck online and ready."

• Vale (COM): "Spartan Vale online!"

The Spartans pass the falling rubble, "flying" close along the mountain slope. Thrusters on their suits control their fall.

• Locke: "Weapons free!"

The Spartans orient themselves feet first to land.

• Buck: "Contact!"

The Spartans tuck and roll upon hitting the ground, propelling their freefall momentum forward. They rush down a mountain slope into a snowy valley filled with Covenant infantry and vehicles.

Buck and Vale fire into a Sangheili Zealot and Unggoy Storm with their shotgun and assault rifle, while Locke leaps ahead and ground pounds a Wraith and two more Zealots, overturning it and stunning the Sangheili. Buck and Vale finish them off while Locke lands and takes out an Unggoy with a Needler.

Buck and Tanaka leap into the air and perform two ground pounds, blasting away more Covenant. Tanaka shoulder-bashes, a Sangheili and Kig-Yar, smashing them both through a boulder which shatters on impact.

Locke shoots away a Kig-Yar while Tanaka fires her SMG, jumping onto and over a Wraith. Her teammates join her in picking off Covenant, some chasing them in floating vehicles. A Phantom floats ahead of them and fires at the Spartans with its chin mounted turret. Flying low to the ground, it scrapes a hill, and Vale uses its momentary confusion to leap onto its open bay doors and rush inside.

Vale knocks two Kig-Yar aside and charges at a Zealot and a Warrior. Both swing their energy swords at her, but she jumps onto the Zealot's arm and forces its blow into the Warrior, damaging its shields and briefly stunning it. The Zealot is then pushed into the Warrior as Vale turns to face the Kig-Yar. Vale punches one of the Kig-Yar in the face and shoots another with her pistol. She kneels to make the charging Zealot trip over her, then stands up to fire her pistol repeatedly into the Warrior's chest and head. She then kicks it and a Kig-Yar out the Phantom, the latter screaming as it falls.

The two hit the ground, Buck running over them as he takes out an Unggoy and a Sangheili with two shotguns blasts. Locke keeps pace to his right, and they leap off a cliff into the Covenant below. Buck ground pounds a lance of infantry, and Tanaka grabs an Unngoy by the face while firing her assault rifle at a Kig-Yar. An Unggoy wielding a Needler lunges at her, but Tanaka catches it, throws it behind her, and shoots it away.

Promethean constructs can be seen fighting the Covenant now. Ghosts rush past firing at Soldiers and Knights, while Phaetons battle the Phantoms overhead. Locke leaps over a pair of Ghosts and pulls the driver out of one of them.

A Phantom, the one carrying Vale, flies low and crashes into a Phaeton, wrecking both vehicles and killing the remaining Zealot onboard. Vale jumps out and uses her SMG to finish off a Soldier. It disintegrates into orange and grey ash.

• Vale: "Heads up!"

The four turn to face behind them, seeing one of the Blockade Runners crashing at the peak of the valley they're in. It hits the ground and begins sliding toward them, bringing an avalanche with it.

• Buck: "Fall back!"

The Spartans turn and run from the incoming starship, Vale picking off a KigYar and Buck finishing off a Soldier and Zealot. They run down the increasingly steep slope as fast as they can, but the crashing ship is coming closer.

As they approach a sheer cliff, Locke lands and rejoins them. Fireteam Osiris assembles and leaps off the cliff with the burning wreck behind them.

FIRETEAM OSIRIS

Cut to Locke's point-of-view, as he and Osiris slide down the cliff, which leads to a small canyon with Covenant below. Buck lunges at a Sangheili Storm, knocking it over and flinging its energy sword to Locke's hand. Another Storm roars and attacks Locke, but the Spartan stabs the sword in its throat. Vale kills a third Sangheili to his left, but there are still plenty of Covenant ahead of them.

• Tanaka: "Incoming!"

Locke looks up to see a fragment of the Blockade Runner falling and crashing into the ground, its impact killing almost all the Covenant there. Only a weakened Commander, Sangheili Storm, and Unggoy Imperial are left, who die shortly thereafter.

{Gameplay}

• Buck: "We could've taken 'em."

• Locke: "Let's move. Vale, keep an ear on comms."

• Vale: "Affirmative."

• Locke: "Buck, Tanaka, pull security."

• Tanaka: "On it."

• Buck: "Aye."

If the player stalls.

• Buck: "Halsey and Jul aren't just going to wait around for us. Maybe we should get a move on."

The team leaves the crashsite and travel along an icy path. It overlooks a valley where Phantoms and other Covenant ships fight Promethean forces. Plasma fire and hard light rounds fly everywhere. A Phantom passing nearby the path that Osiris is on is hit by Forerunner cannon fire, exploding immediately afterwards.

• Locke: "Halsey and 'Mdama are holed up inside a Forerunner structure ahead. That's our target."

• Vale: "So Halsey called us."

• Locke: "She said there was something big out there, and gave Captain Lasky coordinates to find her."

• Vale: "There must be something big."

• Buck: "Or one hell of a trap."

The Spartans come to a site where Covenant infantry try to hold off attacking Promethean Crawlers. A Crawler lunges at a Kig-Yar, who knocks it aside with its shield. On a nearby ridge, a pair of Crawlers savagely tear an Unggoy apart. A Spirit disgorges more Covenant soldiers further back. The Spartans begin clearing out the hostiles.

• Any member of Osiris: "Contact."

• Sangheili: "They must not break through the line to 'Mdama! 'Mdama's work must continue or Sanghelios is lost to us!"

The Spartans kill all the Covenant and Prometheans.

• Vale: "All clear."

• Locke: "Move on toward Halsey's position."

If the player stalls.

• Tanaka: "Gotta respect the Forerunner Builders. They made things to last."

• Buck: "And shoved it in every corner of everything. Can't land on a planet without tripping over something they left behind."

• Vale: "The rate of discoveries has been stepping up lately. Have you noticed that? Ever since Requiem."

If the player stalls further.

• Locke: "Nothing else to do here. We need to move on before Halsey does."

Locke approaches a hill, where Promethean Soldiers appear then vanish away.

• Any member of Osiris: "Forerunner Soldiers!"

• Locke: "Up the cliffs! Get after them!"

He chases the Soldiers, but they phase through a wall of icicles and ice stalagmites, too dense to walk through.

• Locke or Buck or Vale: "Soldier just teleported through that ice wall."

Or

• Tanaka: "Soldier just teleported through that ice wall. It's cracked. We can charge through."

Locke gets a running start and smashes through the ice. His fireteam follows and they engage the Soldiers.

The Spartans come to another valley where there is a heavy presence of Prometheans, including several Soldiers with lightrifles.

• Any member of Osiris: "Prometheans! All sides."

• Buck: "We could push right up the middle, but that'd be rough. Might want to consider flanking them."

• Locke: "Move smart. Fire with a purpose."

After a protracted battle, the Spartans kill their enemies and move into the Forerunner structure at the end of the valley.

• Locke: "Area's clear. Move on. Good work everyone."

• Vale: "I noticed in the briefing Dr. Halsey lost her left arm. When did that happen?"

• Locke: "Jul did it. No idea when or why."

• Tanaka: "Reckon it wasn't an argument, or he'd have cut off her head instead of her arm."

If the player stalls.

• Vale: "Locke, listen to this."

A transmission appears on their HUDs, marked "intercepted".

• Elite (COM): (speaking Sangheili)

• Vale: (translating) "I never believed 'Mdama had as much control over these Prometheans as he claimed. He claws at whatever advantage presents itself. We will see if this mission bears any fruit or whether it becomes yet another in his long list of failures."

If the player stalls further.

• Locke: "Osiris, proceed to Halsey's position."

Osiris arrives in a circular Forerunner room, with many doors and a small platform near the roof.

• Locke: "Systems analyzed. Looks like there's an override switch near the top of the room."

• Buck: "The door's sealed tight."

• Tanaka: "Forerunner security station. Must be in lockdown."

• Buck: "Any way to lift it?"

• Locke: "The Artemis can analyze Forerunner systems. Might be a way to override this door."

• Tanaka: "This Artemis thing one of your old ONI toys?"

• Locke: "Similar. I convinced Commander Palmer to outfit us with prototypes."

If the player stalls.

• Vale: "See anything on the Artemis?"

If the player stalls further.

• Tanaka: "Artemis showing anything?"

The player climbs up to a floating structure and activates the Artemis scanning system.

• Any member of Osiris: "Let's see... this should do it."

The room shakes and the floating structures move. A glowing symbol appears and a door on the ground floor opens. The Spartans pass through to a rocky cave.

• Locke: "The door's open."

• Tanaka: "The Artemis did the trick."

• Vale: "Locke, listen to this."

If the player heard the previous Elite's transmission.

• Vale: "Another transmission."

• Jul 'Mdama (COM): (speaking Sangheili)

• Vale: (translating) "They're assaulting the back of the temple. Bring in the Kraken."

An enormous mechanical leg passes over a hole in the cave's wall.

• Locke: "Kraken sighted!"

• Jul 'Mdama (COM): (speaking Sangheili)

• Vale: ""Hold position. Buy more time." Jul's getting desperate."

• Tanaka: "How'd you learn to speak Sangheili, Vale?"

• Vale: "When I was a kid, I was stuck on a diplomatic shuttle adrift in deep space for six months. My options were be real bored or spend the time getting smart."

If the player stalls.

• Locke: "Move up. Halsey is just ahead."

The Spartans pass through the cave and arrive at a hill, where Covenant infantry are unsuccessfully trying to break through Promethean forces.

• Locke: "Our destination is on the other side of this battlefield!"

or

• Buck: "Entrance to the temple is on the other side of this battlefield."

The Kraken is nearby, firing down with its turrets while Prometheans in the distance attack it.

• Locke: "Watch out for the Kraken! The Covenant are trying to use it to break the Promethean lines!"

• Buck: "I'd rather not get stuck between them!"

A Sangheili Warrior leads the Covenant infantry.

• Kitun 'Arach: "Hold your ground! We must not break!"

Osiris kill numerous Covenant and Prometheans and advance up the hill. More Soldiers hold position near a temple entrance. The Kraken rumbles and begins to march away.

• Vale: "Kraken is falling back! Forerunner defenses were too much for it!"

With the Kraken gone, Osiris eliminates the remaining Prometheans guarding the temple.

• Tanaka: "Area's clear."

• Locke: "Halsey and 'Mdama are somewhere inside that structure. We do this right, we bring our target home and end the Covenant in one move."

If the player stalls.

• Vale: "We know so little about Forerunner civilization. Halsey's obsession with them almost makes sense to me."

If the player stalls further.

• Tanaka: "Should move into the temple. Halsey could take flight at any time."

The Spartans enter the temple and head up a hallway to its interior.

• Tanaka: "Must've dealt a blow to 'Mdama's authority when the Prometheans turned on him. Gained a lot of followers styling himself as a Forerunner prophet."

• Locke: "Jul 'Mdama is an opportunist, not a leader. It was only a matter of time before his version of the Covenant started to break."

• Buck: "Well it could stand to break a little faster if you ask me."

• Locke: "We're close to Halsey's position."

The Spartans arrive a door leading deeper in. Halsey's Debussy music is faintly audible inside.

Locke approaches the door. It opens, and they see a large circular room, and a Promethean Knight, roaring at Covenant attacking it. The Covenant forces shoot off its armor and badly damage it.

• Locke: "Knights!"

or

• Buck: "Heads up! Knights!"

• Tanaka: "New kind too. Like they reported on Oban."

• Locke: "Concentrate fire on the broken armor."

The Spartans head inside, where they witness a large Promethean force consisting of Knights and Crawlers overwhelm the Covenant position near the far doorway. As the Spartans kill the Forerunner constructs, more teleport in.

• Locke: "Don't let them through to Halsey. We need her alive."

If the player stalls in killing the Knights.

• Tanaka: "That glowing point on its back? It's vulnerable."

The Spartans eventually kill all enemies in the room.

• Buck: "Alright, danger is clear."

• Locke: "We move on Halsey and Jul."

If the player stalls.

• Vale: "Halsey's just through that door. We should move."

Osiris approaches the exit door. Fade to black.

{Cutscene}

Osiris assembles at the exit door as it opens to reveal the entrance to Jul's balcony. The four Spartans head down the hallway, weapons at ready.

Cut to bird's-eye-view of the temple balcony. Zealots stand guard and a Phantom holds position near the balcony. Jul paces in the center while Halsey reads her data pad.

• Jul 'Mdama: (angrily) "What is the problem?"

• Halsey: "Hmm, there are several. Would you like to discuss the finer points of casual [sic] reconciliation?"

• Jul 'Mdama: "More human sarcasm."

• Halsey: (smiles) "So you have learned something from me."

• Jul 'Mdama: "You claimed to be able to access—"

• Halsey: "And I can. However, I did not claim to be able to access it instantaneously."

Cut to Osiris heading down the hallway. Tanaka raises her assault rifle to guard the rear while the others reach cover to prep for attack.

• Jul 'Mdama: "The security situation is not stable. There is no time to dither."

Cut to Locke's POV, as he watches Jul circling Halsey and the guards around them.

• Jul 'Mdama: "You will also accord me the respect befitting of the Didact's Hand."

• Halsey: "Mmmm, seems your fingers are in open rebellion, Hand."

• Jul 'Mdama: "Enough!"

Buck sneaks forward and raises his scoped-on lightrifle. He aims it at a Zealot's head.

• Buck: (low) "Hey good lookin'."

• Jul 'Mdama: "Resume your work."

Vale hides behind a barrier and watches a guard to her left.

• Vale: "Eyes on target."

Halsey sighs frustratedly and starts backing away.

• Halsey: "This location does not serve my needs. When she makes another transmission, I must triangulate—"

• Jul 'Mdama: "I tire of this, doctor! You have been chasing shadows for weeks to no avail."

Locke, kneeling, turns his head to Buck and nods. Buck aims his lightrifle, and the targeted Zealot falls. Tanaka turns forward and fires her assault rifle, while Locke dashes to the balcony center, punching away guards and heading straight for 'Mdama.

Vale jumps up to a Zealot guard and leaps off of his head. She lands behind it and the Sangheili chases her while she shoots it with her pistol. When he gets close, Vale flings him off the balcony and the Zealot falls to his death.

Mdama pushes Halsey away and draws his energy sword.

• Jul 'Mdama: "Kill them!"

Locke, watching Tanaka fight the guards, turn to face 'Mdama. Halsey looks back at Locke worriedly.

Locke charges at 'Mdama, then ducks and slides when the Sangheili swings his sword, slashing the Sangheili's stomach with his combat knife. Locke uses his thrusters to abruptly stop his momentum before stabbing 'Mdama in the chest, stunning him. Locke swings around and jumps on 'Mdama's back. 'Mdama tries to shake him off, but Locke stabs him in the neck, 'Mdama groaning in pain.

Cut to Buck hitting a Zealot in the face with his lightfifle before kicking it away. Vale thrusts into the air, gunning down another Zealot with her magnum. Tanaka surveys the site with her assault rifle.

• Tanaka: "Clear."

Spartan Locke standing over the body of Jul 'Mdama.

Locke gets off 'Mdama and pulls out his knife as the Covenant leader falls dead. Locke steps away and turns to face Halsey.

• Locke: "Dr. Halsey. Captain Lasky would like a word with you."

• Halsey: "It took you long enough."

Level ends.

Trivia

• Osiris is the only first mission from any Halo campaign to feature more then one class of enemy forces, in this case Covenant and Prometheans.

Easter Eggs

• The energy sword Locke uses in the opening cutscene can be found behind his landing site, but its battery charge will be depleted.
• Seven Mission Intel pads can be found on this level.
• The IWHBYD skull can be found in the second valley, on a ledge to the left of the entrance to the Forerunner security station.
• The Open Hand Boltshot can be found on a ledge near the cliff where the player first spots Soldiers.
• Two Loathsome Thing Scattershots can be found on ledges by where the Kraken is first sighted. One is on the left and another is on the right.
• The achievement Enemy of my Enemy can be earned on the hill the Kraken is assaulting. Doing so turns the Sangheili Warrior leading a lance of Covenant from an enemy to an ally.
• Seven hidden knives can be found on the level on Legendary. Shooting the first one will turn many of the weapon caches from Forerunner weapons to human ones. Shooting all seven of them will reveal a hidden boss fight in the final temple room, summoning the Warden Eternal and an oversized Promethean Knight but granting the player active camouflage and the Prophets' Bane along with a Type-54 plasma pistol.

Glitches

• If the player leaps into the Forerunner anti-air turret just as it fires, they may get launched over the valley and out of the map. They can then walk through the map as far as the security station, then they will have to initiate the Artemis to load the rest of the level. This can be useful for speedrunning as the Prometheans defending the far end of the valley won't spawn if the player doesn't trigger their spawns by progressing the usual way.

Production notes

• The second cutscene was originally released online as the Halo 5: Guardians Opening Cinematic trailer. Small changes have been made to the final version, such as Vale visibly shooting a Sangheili Warrior as opposed to her fight being obscured by the frame.
• In the final cutscene, Dr. Halsey erroneously refers to causal reconciliation as casual reconciliation.
• The Osiris teammates have different loadouts in this level to reflect the weapons they use in the opening cutscene. Buck has a shotgun and pistol, Tanaka has a DMR and assault rifle, and Vale has a pistol and SMG. However, if they die or despawn then they will respawn with their usual loadouts. This is not the case in co-op mode, which will have respawning teammates start with the different loadout each time.

Gallery

• 

  Concept art of the opening cinematic.

• 

  Tanaka smashes through a boulder.

• 

  Vale jumps onboard a Phantom.

• 

  Locke takes down a Ghost.

• 

  Fireteam Osiris enter the battle.