Following her fight with her mother, Sam goes to Will’s house seeking distraction through rough, dispassionate sex. Afterward, Will is unusually gentle, stroking her hair and asking why she is sad. Sam mentions her mother, then asks about the health of Will’s mother, Diamond. Will reveals that Diamond has pancreatic cancer and about a year to live.

Will shares painful details of his past. Diamond, a trucker’s daughter, attended Harvard on scholarship, where she met the family’s alchiatrist, Amerson, at a party. Starting at age four, Will’s parents tested batches of sand on him, using him as a lab subject. Diamond kept meticulous journals documenting his reactions, treating him as data. His father, Peter—also an alchemist—suffered from depression amplified by sand and the philosopher’s toll. At nine, Will found his father’s body after he had hanged himself in their bedroom.

Sam is horrified by these revelations. Will whispers that he has never told anyone before, and his cold exterior briefly softens to reveal the vulnerable boy underneath. They kiss gently, and Sam feels drawn to him.

Before dawn, Sam receives a meek, pleading text from Connie asking to meet in person. Sam steps onto the balcony and calls her mother back, agreeing to meet the next night. She returns to bed with her back to Will, whose breathing remains rhythmic and even.

On Friday morning, Connie withdraws $14,000 and pays the shipper $6,000 for their midnight departure. She stores the remaining cash in a plastic suitcase hidden in her closet and walks to the grocery store for supplies, fantasizing about reconciling with Sam on the ship and starting fresh in the countryside.

As Connie steps from the curb into the parking lot shadows, a man emerges from a parked car. A gold pin gleams on his collar. When Connie meets his eyes, she realizes with crushing despair that her plan is impossible. Her thoughts shift abruptly from hope to resignation.

An excerpt from The Quantum Mechanics of Alchemy, by an alchemist whose attribution is “Hypatia,” describes alchemy as “a glimpses into alternate worlds” where different choices lead to opposite outcomes—"one’s dream is another’s nightmare” (301).

On the day Sam is supposed to meet Connie, she repeatedly calls her mother but gets no answer. By evening, Sam grows frantic as calls continue to go unanswered. She remembers the last time she could not reach Connie was after the restaurant explosion. When one call routes straight to voicemail, Sam realizes Connie’s phone has died.

Unable to involve the police given her Grand Central ties and her recent killing of Dominique, Sam drives to both the new house she bought for Connie and her mother’s old apartment, finding no one. She calls Will and asks him to use Grand Central’s resources to find her mother. The meeting time passes without any word.

Two days later, Will messages Sam to come to his office about her mother. From the tone of his message, Sam knows her mother is dead.

Sam formally identifies her mother’s body at a police station. Detective Edward Sinclair questions her, suggesting it was a robbery and playing surveillance footage from the store. The murder itself occurred on the side of the building where he claims no footage was available.

At Red City, Will suspects Lumines while Diamond discusses forming a task force. When questioned, a numb Sam confesses that Ari, a childhood friend from the rival Lumines syndicate, knew her mother’s name and admits to secret meetings at their childhood beach. Will tells her it is good she told them. Sam understands that her upcoming meeting with Ari is now a trap to capture him.

In her apartment, Sam’s perfect memory begins failing—she cannot recall her mother’s birth name. Panicking, she takes three doses of sand to regain clarity. The sand induces a hallucination of being eight years old and sick, with her mother tending to her. In the memory, when young Sam asks why Connie had a baby when life was already hard, her mother confesses that she did not want to be alone. Sam sees for the first time her mother’s deep loneliness.

The hallucination ends. Sam is consumed by guilt, believing any small change in her actions could have saved her mother.

On the night of the full moon, Sam arrives at the secret beach, knowing Will and Grand Central crew are watching from the cliffs to ambush Ari. She finds him in the shadows, his face drawn with grief. When Sam tells him her mother is dead, he denies killing her with such sincerity that her anger wavers. They argue bitterly about the deaths of Dominique and Hanover, Sam’s Grand Central guide.

Ari confesses that he loved her and still does. Sam does not believe him. He creates a beautiful bioluminescent display in the ocean, and the sight breaks Sam’s composure. She sobs for her mother. Ari comforts her, pulling her into an embrace and using his bioalchemy to transmute away her tears and calm her anguish, absorbing the pain himself.

As they hold each other, Ari whispers a warning: Lumines is here for her. Isla, a Lumines operative, appears and aims a gun at Sam’s head. Ari shoves Sam out of the way as Isla fires; the bullet grazes Sam’s temple. She realizes Lumines intended to assassinate her tonight.

A violent battle erupts. Grand Central opens fire from the cliffs. Sebastian, a Grand Central operative, kills a Lumines operative and attacks Ari, transmuting his wrist into a metal cuff. Will arrives and swiftly kills two Lumines operatives with elemental alchemy, freezing one man’s legs in ice and bursting another’s veins from the inside.

Will orders Ari taken alive. He grabs Ari by the hair and has him gagged and hooded. Sam feels numb, understanding they were both bait—she to capture him, he to kill her.

Ari awakens tied to a chair in a marble holding room, experiencing sand-induced anxiety and searing pain in his transmuted wrist. He notes a tracker on his bonds that prevents escape attempts. Will and Sam enter. Sam avoids looking at him. Will reveals that they captured several Lumines operatives, including the woman from the beach, and probes Ari about his relationship with Sam. When Ari defiantly says their involvement was mutual, Will’s jealousy flashes.

At Will’s prompting, Sam advises Ari to consider defecting, then leaves the room, her face showing contempt, hatred, and fear. Alone with Ari, Will reveals that he knows Ari is the successor to Reed, the head of Lumines, and that Ari warned Sam of the ambush. Enraged by Ari’s continued defiance, Will has him gagged again.

Will tortures Ari using alchemy, transmuting water in his cells into vapor and making him feel like he is drowning and his heart is being ripped out. Through Will’s fury, Ari realizes that Will loves Sam too, which fills him with panic for her safety.

Sam waits outside the Confession Room, hearing Ari’s muffled cries. An enraged Will exits and orders her to clean Ari up before stalking away. Inside, Sam finds Ari bruised and bleeding. She realizes Will used physical force in addition to alchemy and wanted her to see the result.

While tending to his wounds, she discovers a deep gash on his torso. Ari confesses that Lumines is holding his family hostage in Surat, Gujarat. He explains that Reed ordered him to use Connie to lure Sam into a trap, but when he refused, Reed threatened his family. Ari was then ordered to kill Sam at the beach. He tells her he did not do it because she is his heart—if she dies, he dies. He urges her to find out who really killed her mother to set herself free.

Sam exits and orders guards to fetch Demeter to heal Ari. That night, Diamond and Will summon her to the kitchen. Diamond makes clear they will not return Ari but must keep him alive to appear credible until the planned exchange, then she delegates Sam’s punishment to Will.

Alone with Sam, Will confronts her about Ari. He tortures her by transmuting ice against her thigh, causing frostbite, and threatens to cut off Ari’s hands if he touches her again. He asserts ownership over her and kisses her.

Sam returns to her apartment before dawn, trembling from her encounter with Will. She receives a call from an unknown number—Detective Edward Sinclair, speaking from a private line. The preliminary autopsy is inconclusive, but he found missing surveillance footage from the grocery store parking lot.

He sends her a video link. With her heart pounding, Sam plays it. The footage shows Connie leaving the store and being stopped by a man from a silver car. Sam recognizes him immediately: Will. He touches Connie’s shoulder, and after he drives away, Connie collapses.

Sam is overwhelmed with shock and rage, knowing she will never be able to erase the image. She suspects Diamond gave the order. Sinclair asks if she knows why Will would have done it, but Sam does not answer. He gives her his number, offering to help if she decides to talk.

Sam wonders if Will overheard her balcony phone call with Connie. She begins to suspect her mother may have known enough about alchemy to try to interfere, which could explain Grand Central’s motive. Her feelings for Will turn to pure hatred. Realizing she is in immense danger, she formulates a plan to move against Grand Central before they discover her betrayal and use Ari against her.

Alone in the dark, Sam replays the video of Will killing her mother. Grief hardens into resolve as she recognizes that Grand Central eliminated Connie to protect their secrets. By dawn, her fury has cooled into focus. She finalizes a plan to strike first, preparing to move against Grand Central and protect Ari before they can use him to control her.

Detective Sinclair arrives at the nearly empty El Capitan Theatre to meet Sam. He reflects on the string of mysterious murders—Maclan, fellow victim Kane Zhukov, and Hanover—with no conclusive evidence and the resistance he faces from older detectives. He knows someone in the department hid the surveillance footage of Will and Connie.

Sam appears silently in the seat behind him and pats him down for recording devices. Sinclair reveals that Connie used to work for a Lumines-owned factory under Henry Maclan, a fact Sam did not know. He asks for her help.

Sam hands him a folder containing Grand Central’s financial ledgers, showing illegal sand shipments and illegal payments to Mayor Grayson. She also gives him a video recorder. Sinclair plays the recording, which shows Diamond confronting Zhukov with Will and Sam present, strongly implying involvement in his death. On the recording, Diamond also states that Sam was responsible for Maclan’s death. Stunned, he realizes that Sam is a killer and asks why she is incriminating herself.

Sam offers herself as an informant with specific terms: Grand Central holds her friend Ari Rathod and plans to kill him during a prisoner exchange in two days. She demands that Sinclair raid the exchange at Diamond’s estate to give her a chance to save Ari. She warns him to come prepared for the impossible, hinting at alchemy without naming it, and assures him his chief will approve the raid.

Sam disappears without a sound. Shaken but determined, Sinclair leaves the theater and immediately calls the department to speak with the chief.