The penultimate episode of Season Two is here, with action on Onyx escalating towards a climactic showdown at our ultimate destination: the Halo ring itself. But dark and ancient secrets from millennia ago are stirring...

Beware, for there are spoilers ahead!

EPISODE SUMMARY: THERMOPYLAE

The Master Chief and Makee converse as they appear in a vision of the vast green fields, forests, and lakes on the Halo ring. The Chief tells Makee that he saw her on Reach with the Arbiter, bringing about the death of millions of people, to which Makee says that he would do the same to High Charity.

Makee insists that either side controlling Halo will use it to eradicate the other side, as war is all they know, but the ring does more than destroy—it holds the seed of life itself that could be used to build a world of peace, and it belongs to her and the Chief. Sangheili suddenly breach the vision and Makee is pulled away from the artifact aboard the Arbiter’s ship, and an electromagnetic surge passes through the ONI facility back on Onyx as the Chief releases his grasp on his artifact.

Makee grabs Cortana’s data chip but is pursued through the ship by the priest Uto ‘Mdama. Cortana appears and speaks in Sangheili to Uto as a distraction, giving Makee an opening to stab the priest with an energy dagger before she confirms to Cortana that she has found the Halo’s location.

DISPOSABLE HEROES

James Ackerson meets with Admiral Parangosky on Onyx who deduces that the strike team he sent has failed to locate the Master Chief and notes that if his survival is learned of then it will lead to inconvenient questions about Reach. Ackerson says they won’t have to worry about that, to which Parangosky points out that he was in charge—the blame would fall on his shoulders.

As the central holotable comes back online, Cortana’s signal on the Arbiter’s ship is reacquired in the Soell system where it has emerged from slipspace—along with the Covenant’s entire First Fleet of Solemn Accord. Significant energy is detected at the center of the system causing a disruption in the hologram and Parangosky orders Vice Admiral Stanforth to dispatch UNSC ships to that location, then tells Ackerson to ready the Spartan-IIIs. Ackerson argues that they were trained to execute specialized missions, not assault a Covenant fleet, to which Parangosky says it’s his job to prepare them while she decides how they’re used.

As Condors begin to arrive at the Soell system, Parangosky speaks with the Spartan-III commander of the lead dropship, but all of the Condors in the first group suddenly blink off the screen, having all been destroyed.

Parangosky orders the second wave to be deployed, which Ackerson believes is an unsound tactical decision as they will be wiped out as well, but Parangosky is willing to sacrifice all of them because this isn’t just another battle. This is the battle to claim the Halo, and if the Covenant take it then there won’t be another day for humanity to fight.

TRAUMA LOOP

Soren and Laera continue searching for Kessler within the ONI complex, causing Soren to reminisce about his early days of Spartan training and how discovered who he was through its torturous trials, recalling fighting alongside Riz, Kai, Vannak, and John—they stood, fought, and lost together.

Laera asks what they are going to do about Kessler, to which Soren says nothing—tonight is his opportunity to discover who he is, which infuriates Laera. She deduces that all the time Soren spent looking for Dr. Halsey wasn’t about bringing her to justice, it was him trying to find his way back. Soren says that being a Spartan meant something, but Laera argues back that he isn’t a Spartan, he has a life and a marriage and a son, and she won’t let the UNSC turn Kessler into a killer.

Soren watches as the training exercise begins and men with batons rush at Kessler, but he steps in and attacks them. More guards enter and drag Laera and Kessler away Soren continues to fight them off.

DO GOOD SOLDIERS FOLLOW ORDERS?

After leaving the artifact chamber, the Chief is halted by Captain Briggs and a group of ONI troops. Briggs gives the order for her troops to take the Chief down, but the soldier holding his weapon at the Chief hesitates. The Chief says he’s been on his side of the gun, not asking questions, and that a bullet can’t be taken back once fired—which is why Briggs wants him to be the one to fire. The soldiers refuse to fire, telling Briggs to do it herself. Briggs raises her gun but is knocked out by a hit from behind by Kai-125.

The Chief sees a group of Spartan-IIIs moving out as Kai attempts to explain her actions, the Chief accuses her of making the wrong call as she put her trust in people who wanted them dead. Asking where they’re going, the Chief points out Cortana guiding them so that he can get his Mjolnir armor.

Examining the system spike, Ackerson runs simulations to see if the explosion of a Covenant vessel can encompass a planetary, then system-wide scale. As he is about to leave the room, the doors open to reveal the Chief and Kai.

The Chief grabs Ackerson by the neck and lifts him off the ground, demanding to know where his armor is, Ackerson says it’s behind a biometric lock and reveals that Parangosky lied about the spike—it doesn’t do what they told the Spartan-IIIs, it’s not a system override, it turns a Covenant ship’s fusion drives into a massive bomb that can eradicate their fleet, the UNSC fleet, and possibly the Halo itself. Parangosky is throwing Spartan-IIIs in waves at the Covenant because she doesn’t need all of them to make it, she just needs one. This is her insurance policy, so that if the UNSC can’t get the Halo then neither can the Covenant.

The Chief asks when Ackerson suddenly cared about Spartans, to which Ackerson says that the Spartan-IIIs are his life’s work, but the Chief is unsympathetic and says he’s heard that before.

Arriving at the vault holding Silver Team’s Mjolnir armor, the Chief walks over to Vannak-134's armor and laments that he couldn’t save him. Ackerson asks what they’re going to do, the Chief says that his intent was to kill Ackerson, but decides that Ackerson will tell everybody what he and Parangosky did to Reach. The Chief then tells Kai that he can’t go with her, he intends to go to the Halo while Kai says that she will join the Spartan-IIIs.

GIFTS FROM THE PAST

Kwan, Miranda, and Halsey are inside the ancient cavern on Onyx. Halsey and Miranda debate the mistake that Miranda alluded to her mother having made, as she saw it as a purely mathematical problem whereas there is a linguistic feature to the “puzzle” as well, Miranda’s area of expertise.

Halsey tells Miranda that she found a DNA sample when she opened the first part of the trove, explaining that it was both human and not, and she believed it was an invitation to unlock the full potential of humanity. She gathered a team and searched for people who exhibited traces of the sample’s genetic sequences. Kwan interrupts to remind Halsey that she took children, to which Halsey says that she—and humanity—needed the Spartans. Halsey then asks Miranda to show her what she found, and Miranda reveals a small, locked container.

Miranda asks Halsey what happened to Jacob Keyes and considers that survivors are scattered across the galaxy, but Halsey confirms that she saw what happened. Kwan makes a star map appear, but she figures out that it’s not a map—it's a clock. Recalling the cave markings on the Rubble, Kwan moves the constellations into the right places which opens the locked door. Inside, a light bridge appears.

Crossing the light bridge, Halsey places the device Miranda acquired onto a Forerunner door, opening it, and inside they find a laboratory filled with phials—and at the far end of the room lies a curled up humanoid body clutching something in its six-fingered hand.

Suddenly, the phials begin to break and the door slowly starts closing, prompting the trio to run back across the light bridge as the whole facility lights up. Back in the room with the clock, the hologram has changed with flashing red lights, and Kwan recalls the other things she saw on the cave wall—the monster, the word “growth”—and runs off.

Miranda reveals that she retrieved the device that the dead Forerunner was holding. Examining it in Miranda's lab, she finds a way to open it, but finds that Halsey has disappeared after a voice over the comms declares that there are unauthorized personnel in the base.

FATE OR LUCK?

Corporal Perez and Javelin Team suit up in their armor and she looks at the coin the Master Chief gave her for luck. The Chief approaches Perez alone and she is stunned to find that he is alive. She asks if he’s coming with them, but the Chief tells her he has a different mission. They consider the story he told her about calling the coin a dozen times when he was a child, and Perez believes that the Chief made it so it was heads.

Ackerson rejoins Parangosky as they observe a holographic display of the action taking place in the Soell system, and she reveals her knowledge that he ran an unauthorized simulation of the spike code. Ackerson asks her about the Spartan-IIIs, as they put their trust in him after he told them they could win, but they are interrupted when an unauthorized Condor takeoff is detected. The Master Chief responds over the comm, bringing a smile to Ackerson’s face that prompts Parangosky to order Ackerson be restrained, and as he is carried away he says that when the story of this is told they will listen to the Master Chief.

Meanwhile, Arbiter Var ‘Gatanai approaches Makee and says that the priest’s loyalists are dead but the Covenant fleet has found them. The Arbiter says that Makee has shown him his redemption and Makee then brands herself with the Mark of Shame, binding the Arbiter’s loyalty to her, though Makee notes that they are bound to the ring.

Arriving at the Soell system, the Chief finds the coin he gave Perez on the flight console. Upon exiting slipspace, the Chief finds the Covenant fleet and sees the Arbiter’s ship heading for the Halo.

CORE CONNECTIONS

Let us speak of old things—hidden, terrible things from a time long forgotten...

From one of the Magellanic clouds of stars beyond the reaches of our galaxy, a fleet of ancient starships arrived at our cosmic border. These vessels were of unknown design and on an automated trajectory, carrying neither passengers nor crew, but a curious cargo: millions of glassy cylinders containing a fine, desiccated powder.

Wreckage of these mysterious ships were discovered by the Ancestors on worlds both inhabited and empty. Upon examination, they were found to contain short-chain molecules, simple and inert—organic, yet seemingly neither alive nor capable of life.

Experiments on animals demonstrated desirable psychotropic effects, improving their domestic behavior, and over several centuries this powder was used without ill consequences.

But in time, the long-term effects of this powder became known. A peculiar growth began to emerge, initially thought of as a natural mutation, until these animals—natural herbivores—began consuming these growths, and eventually the animals themselves.

This set off some sort of biological timer, a signal for expansion... as these growths soon began to manifest in the ancient human Ancestors.

Know that energetic and tenacious as life is, it has an antithesis just as powerful.

It is that thing that we must obliterate.

DECLASSIFIED

With so much to process from this episode, Sydnee Goodman is joined by Jen Taylor (Cortana, Dr. Halsey, and The Weapon) and the VFX team to learn more about Cortana and how she was upgraded this season.

Also joining for a friendly fireside chat is Charlie Murphy, who takes a break from her quest to claim the Halo ring to talk about Makee’s journey over Season One and Two—and there’s plenty more behind the scenes goodness where that came from!

(NOTE: Some regions may not be able to view this episode.)

That’s a wrap on the penultimate episode of Season Two, and what a ride it’s been!

The final threads are coming together, setting the stage for an epic action-filled finale that is just under a week away.