Running late, Sasha takes the key from Kumar’s desk but leaves her and Levi’s charts as they are. When she reaches the supply closet, Wilma suits her up and sends her running to meet her team, as Unit Seven is heading toward the surface in an unauthorized exit. Over her helmet comms, she hears Unit Seven waiting in the holding box; Tristian refuses to leave without her. Levi gives Sasha the call sign “Phoenix.” She arrives just in time.

Suddenly, Burdon and Kaleo appear at the closing steel doors, and Wilma delays them. Kaleo quickly disarms and restrains her while the others jam metal into the mechanism to keep it open. Unmoved, Tristian tells Burdon that she always wanted him to lead the Force; now he is. The unit escapes to the surface, determined to find the hidden supplies despite the lockdown so that they can save Haven.

As they run toward the Abyss, the group processes what they have done. Rumi reveals that she falsified Haven’s radiation readings and punctured the oxygen tanks to delay pursuit; Tristian helped her. Damien is shaken that only Tristian, Levi, and Rumi knew in advance. Tristian later says that he limited knowledge to protect them if the plan was discovered.

At Outpost One, the unit resupplies. Sasha fastens Kumar’s key around her neck. During the long run that follows, she becomes emotional under the weight of grief and trauma; Levi stays close and holds her hand through the worst of it. That night, Sasha wakes to find herself tucked against Tristian. When she tries to pull away, he quietly asks her to stay. He admits that when he killed the men on patrol, he did so because he initially believed that Sasha was their murder victim. He apologizes for being too rough when they had sex; she tells him that she has no regrets. Morning brings a brief, ordinary peace over shared food.

At the Abyss, Tristian lays out the plan: Some members will remain above as armed cover while others descend into the tunnels without suits. Rumi refuses to go below, arguing that she’s most useful with a weapon above. Patrick then refuses to enter the tunnels and convinces Ingrid to swap gear with him, telling Rumi, “If you stay, I stay” (373). Tristian, Sasha, Ingrid, and Isla descend.

Their unease intensifies when none of the traps go off and their radios cut out underground. Tristian splits the group, sending Ingrid and Isla down a route that he has already scouted while he and Sasha take an uncharted fork. He later admits that this plan was Rumi’s idea; she didn’t want him to take reckless risks alone.

As they search empty room after empty room, Tristian tells Sasha more about the mutiny that Burdon masterminded. After Burdon’s coup dissolved the Angels, Tristian realized that Command couldn’t be trusted. For a year, he strategically resumed a relationship with Burdon in order to access communications and intelligence across sectors. He chose each member of Unit Seven deliberately, looking for people who still had someone to fight for—proof that they had preserved their humanity. When he contracted an illness and lay near death in the Ward, he heard Sasha’s voice urging him to stay; immediately after recovering, he ended his faux relationship with Burdon, who retaliated by making the Abyss mission a competition between the Exploratory Units. The recent lockdown has convinced him that Command is using the crisis to thin the population, and he believes that a widespread mutiny in Haven is now inevitable. He reveals that he has just refused Burdon’s latest offer to become her second-in-command in exchange for avoiding a trial for the men he killed on patrol.

Sasha recognizes that Tristian doesn’t expect to survive. She admits to being afraid of everything, especially of losing him. He says that fear is bearable if it isn’t faced alone. She can’t bring herself to push him away. He kisses her gently, and they have unhurried sex on the tunnel floor.

Afterward, Sasha notices a camouflaged gray box with a small indentation. Kumar’s key fits perfectly. Together, she and Tristian activate it, and a hidden door grinds open.

Beyond the door, lights flicker on to reveal a large room stacked with supplies. Tristian embraces Sasha in relief. Radios spring back to life, and he announces the mission’s success. Ingrid and Isla confirm that lights have come on in their section as well.

They explore the cache: One room holds building materials, supplements, medications, and medical gear. They also find an entire room filled with preserved art, including a Picasso. Tristian says that his mother believed art was essential and that it might restore hope in Haven.

The narrative reveals that Kumar knew from Tristian that the current mission was code-named “Hope.” Deeper in the cache, Sasha and Tristian discover a colder room containing rows of oblong pods. Wiping dust from one, they make out the label: “Tactical Artificial Biotech Intelligence Tracking Human Algorithm,” or TABITHA (391). Before they can investigate, the rest of Unit Seven arrives, drawing Tristian and Sasha away from the strange room.

In an emotional reunion, the team celebrates their discovery. Damien and Isla have discovered gems and emerge covered in jewelry. Tristian thanks everyone for their sacrifices, honors Lily’s loss, and credits the unit with giving Haven a future.

While the others celebrate, Sasha slips back to the pod room. The key in her fist cuts her palm, and a drop of blood falls onto the glass. Steam swirls inside the pod and clears. A gray-eyed woman stares back, smiling. Suddenly, a gunshot sounds from the main room.

Sasha runs to find four suited figures, led by Kaleo, with weapons drawn on her unit. He explains that activating the cache simultaneously activated Haven’s technology—the map, suits, and radios—revealing the Abyss and their location to Command. Knowledge of the supplies will no longer protect Unit Seven from punishment for their mutiny.

Violence threatens to erupt. Rumi runs forward to shield Kaleo, making her allegiance plain. Patrick is devastated by her betrayal. He recounts how he found a devastated Rumi after the war and swore to stay by her side if she kept living. Rumi admits that she has been withholding the truth about Kaleo for two years. Patrick leaves, his grief echoing in the silence.

Kaleo’s companions remove their helmets; they’re Peterson from Unit Twelve; Lawrence, a blond woman; and Wilma, whose takedown by Kaleo during Unit Seven’s escape was staged. Kaleo explains that he hasn’t been working against Unit Seven. During the Angels’ disastrous mission, he suspected Balakin of being Burdon’s operative and was maneuvering to stop him. After the coup, Kaleo strategically got close to Burdon to find proof of her crimes. He discovered a letter from Dr. Uri that congratulated her on the coup and referenced the key. Tracking this key became his mission. He, Rumi, and Kumar worked together: Rumi delivered the key to Kumar, who passed it to Sasha when plans changed. Kaleo proves the truth of his account by accurately describing the key that Sasha now holds; he says that the key was originally meant for Tristian, but Kumar believed that Sasha would do the right thing with it.

Rumi also reveals that some observatory team members may have faked their deaths. Patrick and Ingrid return, having found a viable exit. After a grudging lowering of weapons, Sasha slips back to the pod room to discover that the woman she saw is now gone. Not knowing what to think, she lies to Damien and claims that she went to the room because she had dropped a knife. She walks out, shaken by this mystery but not yet willing to tell the group about it, given the tense circumstances.

Both groups cooperate to extract the most urgently needed medical supplies through the exit that Patrick and Ingrid found. Tensions remain high. Kaleo has everyone disable their suit communicators and then destroys his tracking tablet, disrupting Haven’s ability to follow them. His actions will likely send any pursuit in the wrong direction for at least a day.

A secret dirt tunnel leads them back toward Haven. A man—one of the Moles from Expansion Sector leader Terral’s hidden crew—meets them and guides them partway inside. Kaleo explains that the Moles are people whom Haven’s records falsely list as dead; this secret Expansion team is digging toward the Abyss under Terral’s orders. The guide disappears before they reach the inner tunnels.

As the group rests, Sasha privately tells Tristian what she saw in the pod. He kisses her, locates the key against her skin, and pockets it without explanation. He tells her not to reveal what she saw to anyone else. Later, when she struggles to express her love for him out loud, he fills the silence by saying that he loves her.

Elsewhere, Isla confronts Rumi over her deception; Rumi fires back that Isla’s choices have hurt those around her. Damien tries to mediate, but the unit is fractured.

As the group prepares to re-enter Haven’s main tunnels, Kaleo’s plan requires a show of force. Lawrence cuffs all of Unit Seven except Tristian and Sasha. To sell the scene, Levi taunts Kaleo, who hits him. When asked why the guide can’t come, Kaleo answers simply that the man is dead. As footsteps approach, Kaleo grabs Sasha to maintain his cover as Burdon’s minion, and Tristian attacks him. Burdon arrives with her weapon raised.

Burdon marches Tristian and Sasha to her office at gunpoint, has them searched, and sends Kaleo away. She confronts Tristian with Sasha’s and Levi’s real medical charts, which were recovered from Kumar’s office. She forces Tristian to read the ID numbers aloud, confirming the switch that Sasha made. As punishment, Burdon declares that Sasha’s new health score (really Levi’s) disqualifies her from the Force. Desperate, Tristian offers to give Burdon anything in order to keep his team together. Her price is that he must become her second-in-command.

Back in the living quarters, the unit is already there; they were released after a brawl in the holding cells, in which Kaleo publicly protected Rumi from her attackers. Henderson is also present, having attempted to help while the unit was above ground. Tristian announces that Levi now commands Unit Seven. Sasha then outlines Burdon’s sentence: Tristian will be Burdon’s second, while Sasha’s current health score will disqualify her from the Force by the next moon. (She confesses that she swapped her charts and ID band with Levi in the Ward.) She also reveals that Unit Seven’s Exploratory status is permanently revoked and that they’re reassigned to the guard shack while Jaxon’s unit takes their place above. Tristian leaves without a word.

In the conversation that follows, Damien inadvertently reveals that Henderson’s call sign is “Snake.” Sasha realizes that Kumar’s cryptic warning about finding a “snake” meant identifying Henderson as a spy for Burdon. She also realizes that Rumi (whose call sign is “Eagle”) was the “bird” who left the key for her. She deduces from Kumar’s dying instructions that she must protect the Moles in Expansion (“the dead”). Across the room, a meditating Rumi opens her eyes and nods, silently confirming Sasha’s realization.

An unspecified time later, Sasha is working a labor shift in Expansion. Reassigned and stripped of her Force rank, she wears a gray band again. Unit Seven has fragmented; Levi now commands, and the others are trapped in the guard shack. Kaleo, also exiled to Expansion, works beside her.

Sasha’s focus has shifted from survival to living for those she loves—including Tristian, whom she rarely sees. Despite her failures, she’s unwilling to give up. Kaleo calls her “Phoenix,” but she rejects his right to do so. He asks if she ever found records for the men Rumi suspected of faking their deaths; she has not. Then, with a particular edge, he asks whether she has been thinking about “dying”—a hint at faking her death, going underground, and becoming a Mole. The exchange ends unresolved, pointing both of them toward a dangerous, unnamed quest.