“

Doctor Halsey makes contact with the Forerunner known as Librarian.

”

Key is the ninth episode of Spartan Ops. It was released on February 11, 2013. In this episode, ONI has ordered Doctor Halsey assassinated, and Sarah Palmer is slated to pull the trigger. Lasky, in an effort to save Halsey's life, sends Fireteam Majestic to stop Palmer. What they discover may be the key to the future of humanity.

Chapters

#	Name	Location	Description
1	The Search for Halsey	Cyclone	"Jul 'Mdama has abducted Dr. Catherine Halsey. All fireteams dispatched to investigate her whereabouts."
2	Clean Up	Control	"Fireteam Crimson dispatched to back up Boa Squad in holding UNSC base at Covenant Control."
3	Science Mountain	Apex	"Spartans deployed to investigate Halsey transmission at Apex. Scorpion tank drop requested."
4	Revenge	Lockup	"Covenant detention facility targeted for shut down. Spartans on the ground to level structure."
5	The Hammer	Lockup	"Numerous Covenant forces inbound on Lockup. UNSC ground teams are holding the area and request Spartan reinforcements."

Opening cinematic

Cut to Sarah Palmer on Infinity's armory device, having just finished suiting up. Captain Lasky watches her step off.

• Lasky: "She's only out here because of me. And we're soldiers, not hitmen."

Palmer receives her M6H pistols from a nearby technician.

• Palmer: "Halsey knew what she was doing when she made friends with the bad guys."

• Lasky: "I'm serious. We-we shouldn't have to execute a civilian."

Palmer receives her helmet from the technician, and turns to face Lasky.

• Palmer: "No. But it has to be done. And I don't trust anyone else to do it right."

The two begin leaving the armory to head to the hangar.

• Lasky: "There has to be another way. I-I mean-"

Palmer stops and stares at Lasky.

• Palmer: "I know what you mean, Tom. And I won't see you court-marshaled over that woman."

Palmer continues walking away, stopping when she reaches her deployment panel.

• Lasky: "Sarah, stand down!"

• Palmer: "Orders are orders, Tom. This isn't my first rodeo."

Palmer puts on her helmet. The floor lowers to deploy her to Requiem's surface.

• Lasky: "I don't suppose it is. ...Roland, where's Fireteam Majestic right now?"

HALO: INFINITY

Cut to a landing Pelican. Fireteam Majestic waits for it to land.

• Madsen: "Ride's here."

The SPARTAN-IVs step aboard. Gabriel Thorne escorts Dr. Henry Glassman inside. A life-size hologram of Captain Lasky appears.

• Lasky: "Fireteam Majestic. Doctor Glassman. Glad to see everyone alive and well."

• DeMarco: "Captain Lasky, wasn't expecting to see you here sir."

• Lasky: "Majestic, I have a personal favor to ask. Doctor Halsey has been abducted."

Cut to inside the Forerunner shrine. Inside is a ghostly expanse, where the Librarian lives. She towers over Halsey and spreads her arms.

• Librarian: "Welcome."

Halsey stares at her in awe.

• Halsey: "You...You are Librarian. Wife of Didact. There is a Covenant cultist leader outside. He thinks you have something valuable."

• Librarian: "He is correct. But what I have is not for him. It is for you. Catherine Halsey."

Cut to many patrolling Sangheili. Cut to Sarah Palmer, who pulls out a knife, sneaks up behind an Elite, and stabs its neck. The Elite gurgles and dies, and Palmer sets down its body before carefully sneaking ahead.

Cut to Sniper Alley, where many Elites patrol its entrance. Gabriel Thorne sneaks by while cloaking, but one Elite senses his presence and looks around for him. Thorne uncloaks behind him, and the Elite spots him and whips out his energy sword, as do the others.

• Sangheili Storm: "(Sangheili) Intruder!"

• Thorne: "Majestic!"

Thorne recloaks and the Elites swings at him, but Hoya, Madsen, and Grant fire down on the Sangheili from the ledge above the entrance.

• Grant: "Up here, hinge-heads!!"

On the ground, DeMarco attacks the Elites with his energy sword. He assassinates one, swings the legs out from another, and overpowers the clash of a third. As he turns to defend behind him, his back bumps into the decloaking Thorne, who has been picking off Elites with his assault rifle.

• DeMarco: "We got this! You get the old lady!"

Thorne nods and covers for DeMarco with a few more shots. He then turns and dashes inside the base, recloaking as he does so.

Cut to Jul 'Mdama in front of the Librarian's shrine. He approaches Halsey's unconscious body, which is floating inside the beam.

Cut to the Librarian inside. She holds up two halves of a small thin device.

• Librarian: "This is the Janus Key. It offers the real-time location of every piece of Forerunner technology in the galaxy."

• Halsey: "Every piece?"

The Librarian connects the two pieces together. Holograms of star systems burst from it and surround the two women. Halsey examines them in fascination.

• Librarian: "We did not create so much without a means to catalog it all. This was meant for my husband to help you people...when his meditation was complete."

The Librarian separates the pieces, and the holograms disappear. She holds out the pieces to Halsey.

• Librarian: "Take this key to the Absolute Record. Use what you find to propel humankind."

• Halsey: "Why give this to me?"

• Librarian: "Requiem's time is at an end. The key and what it details must not be lost."

Halsey cautiously takes the pieces from her. With a flash, Halsey is flung out of the artifact, still clutching the keys. 'Mdama catches her, notices a piece, and takes it from her.

• Jul 'Mdama: "(Sangheili) This is the Librarian's gift?"

'Mdama drops Halsey and examines the half-key, unaware that Halsey has the other.

• Jul 'Mdama: "(Sangheili) This is what we came for? Full of the Forerunner's secrets?"

One of 'Mdama's guards suddenly screams and is thrown to the floor. Thorne uncloaks and pulls out his assault rifle.

• Halsey: "Thorne!!"

'Mdama grabs Halsey and holds her in front of him.

• Jul 'Mdama: "(Sangheili) Blasphemy! Kill the intruder!"

The other guard swings its sword. Thorne ducks, hits its head, then fires an assault rifle burst into its chest.

• Halsey: "Thorne, take the key!"

Halsey tosses her half of the Janus Key to him. Thorne catches it, and examines it. He looks up upon hearing a gunshot, and sees an Elite about to attack him fall dead from Palmer's sudden rescue.

• Thorne: "Commander Palmer?"

• Jul 'Mdama: "(Sangheili) Knights, protect me!"

Promethean Knights phase in to attack the Spartans. Palmer takes aim and shoots Halsey in the shoulder.

• Halsey: "Ahhh!"

Knights phase in. DeMarco swings at one with his sword.

• DeMarco: "Majestic, engage!"

The Spartans fight the Prometheans. Thorne and Palmer charge ahead chasing 'Mdama, who is carrying Halsey away. Madsen picks off two Prometheans with his sniper rifle. 'Mdama reaches the end of the room and turns to face the charging Spartans. A Knight phases in, grabs 'Mdama and Halsey, and snarls as it teleports them away.

• Palmer: "No!!"

The two Spartans stop, having just lost 'Mdama. Fireteam Majestic rejoins them.

• Palmer: "What the hell are you guys doing here?!"

• DeMarco: "Captain Lasky sent us to rescue Doctor Halsey."

• Palmer: "Rescue her? She's a traitor!"

• Thorne: "All due respect, Commander: if she was on Jul 'Mdama's side, then why would she make sure I get this before he could?"

Thorne holds up the half of the Janus Key. Fade to black.

Gallery

• 

  Palmer suits up.

• 

  Halsey meets the Librarian.

• 

  Palmer prepares to assassinate an Elite.

• 

  Jul 'Mdama takes one half of the Janus Key.

• 

  Thorne shows Palmer the other half of the Key.

Trivia

• During the filming of motion capture for the cutscene, highlighter pens and a Dos Equis box were used as props.
• In the trailer for Episode 9, the footage of Palmer on the armory machine is played backwards.