Echo puts Margaret Cavendish and Zera Yacob in conversation by changing the virtus’ setting to one that allows them to walk around. Zera gives Echo more information about the masks. After the time of the pharaohs, people believed masks were capable of capturing human consciousness. Based on this conversation, Echo concludes that this is the reason for the woman’s attack on the library and Echo.

Zera encourages Echo to move quickly to stop them. Gina, who has been spying on the conversation despite privacy settings that are supposed to prevent that from happening, interrupts to tell Echo she hears sirens coming toward the library.

Echo is angry that Gina was spying on her but asks Gina to cover her tracks so no one will know about her searches and the mask. Such a task is supposed to exceed Gina’s programming, but she manages to complete the task.

Echo runs out of the building but realizes that she has forgotten the mask. Only two cars pull up to the library, one containing Detective Reid and another containing Percy, whose presence surprises Echo since he is supposed to be back in Atlanta. Percy is dressed in expensive clothes and has a car that his salary as her supervisor shouldn’t cover, so Echo concludes that he has more power on the NLC than he claims.

Reid refuses to do anything else and leaves. Echo leaves the building. She sees Walter outside the library. Echo uses her eyes to indicate he should ignore her. Echo confronts Percy about why he’s there. Percy repeats the first part of his favorite quote about the fluid nature of truth, and Echo finishes it —“‘And a lie with enough kick to it makes you an asshole” (88).

Echo goes to a café with Percy. Percy explains that the actual backer of the People’s Library is Universal Trust, the company that oversees the UBI program and that is ostensibly devoted to the survival of humanity. Anger over the UBI test has led many to distrust Universal Trust.

Echo isn’t happy to find that both she and Percy work for the group. The People’s Library is the ultimate in digitization and doesn’t focus on humanity, so it is an odd project for Universal Trust to be involved in. Echo realizes that Percy has been withholding information from her and is likely still not telling her everything he knows. Percy explains that he actually lives locally.

When Percy leaves, Echo retrieves the mask. She has an angry conversation with Gina, criticizing Gina for spying on her. Echo knows it is naïve to believe that privacy exists, considering that the Model (the AI that manages all AI currently deployed) uses cameras to track everything everyone does.

Echo has Ada check out Jesse Cooper once again. She tells him she needs tactical advice on how to respond to what has been happening in the library. He tells her he is pleased to finally be focusing on the present instead of the past.

Echo provides Jesse with information about Universal Trust as well as Human.exe’s aims. She notices Jesse is taking notes—an oddity given that virtus are dormant when not checked out, meaning notes wouldn’t be useful. When she asks him why he is taking notes, he glitches for a moment and fails to answer her question.

Echo thinks about giving the mask to the police and just going back to being an ordinary librarian. Jesse guesses what she is thinking and affirms her ultimate decision, which is to continue her pursuit of the mystery of the mask and discover what those responsible for the mask are up to. He agrees to strategize with her. He suggests that she see the mask through the lens of her synesthesia, which associates colors with numbers. Perhaps the colors indicate a coordinate of an important place.

The conversation takes an odd turn when Jesse asks her not to shut him out and that she exercise caution. Echo longs to reach out to him but knows there will be nothing there since he is a virtu. She is nevertheless developing feelings for him. She checks him back in. Echo thinks about how she exercises a high degree of control over the people in her life, especially her employees; the same applies to the virtus.

Echo has Ada check out Margaret again. After a contentious conversation, they agree to treat each other with mutual respect after Echo reminds Margaret she has the power to delete her.

The two strategize. Margaret recounts her disruption of a 17th-century meeting of the Royal Society of London, an all-male scientific group. The disruption ended in arguments rather than a productive conversation, but Echo wonders whether she can do something equivalent by entering the world of the virtus from the inside. Searching the collection virtually might reveal Percy and Universal Trust’s actual plan, and because all employees contributed a short family history video, a digital record of Echo is already in the collection.

Gina, who has been listening in despite Echo’s privacy settings, interjects to offer to create a mental connection between Echo in the physical world and Echo in the virtual world, using Ada to access virtual space. Echo suspects someone has hacked Gina, but she ultimately agrees to the plan. The transformation works once Echo puts on the mask. Echo’s physical body remains in a chair.

Echo is in Margaret’s room and feels insubstantial and alarmed by the sight of her “diaphanous hand” (105). When she tries to see her physical body, Margaret shows her a blank wall that only opens when the virtu is checked out. Echo calls out to Gina and Ada, but neither answer. Echo is terrified and begins drowning in memories of her life.

Echo is submerged in her memory of when she learned that she had synesthesia. When she emerges from the memory, she is again in Margaret’s room and has the chance to look at her surroundings. It is 1670, and Echo is in the north of England. The room is sumptuous, and Echo can see the beautiful landscape outside. However, all the books in Margaret’s substantial library are blank, and the virtus are only allowed to occupy the rooms that are visible to the patrons who check them out. When they aren’t checked out, most virtus sit in these limited spaces doing nothing.

Margaret explains that the Model, the AI that guides the world and programmed her, engaged her in years of examinations, which did pass some time. She understands that Echo has great curiosity about virtual space, but she reminds Echo that their main task is to figure out how to stop Human.exe from destroying the library and the virtus.

Echo feels guilty as she considers all the clues she ignored about the empty lives the virtus live. Margaret doesn’t blame her and tells Echo that Echo is just as much a puppet as the virtus are. Perhaps Percy has the answers. Margaret asks her to focus on the problem at hand.

Echo once again tries to contact Gina, without success. She then tries to check herself out, but that doesn’t work either. She is finally able to reach Ada. Echo asks Ada where Gina is, and Ada tells her that Gina is attached to Echo’s body, which Echo takes to mean that Gina is still embedded in her body through the subdermal implant. Echo asks Ada to connect her to Gina. Ada says the process is so complex that it will take some time.

With time to spare, Margaret suggests to Echo that they find someone who can help them get to the bottom of what Human.exe and Universal Trust are doing. Echo asks Ada to check out for them someone with a math background.

Ada first takes them to Brahmagupta in the year 640 BC. Brahmagupta is most associated with the concept of zero as a representation of the void or nothingness. Keeping in mind the empty lives of the virtus, Echo answers Brahmagupta’s questions about the 21st century to allow him to have stimulating conversation. She then explains their conundrum, namely, why the number zero is so significant to Human.exe. Brahmagupta explains that the concept of zero is highly contested because it gets at the origins of human consciousness, which seemingly emerges from the void or nothingness. Brahmagupta concludes that someone is seeking the source of consciousness.

Echo next has them check out Zera Yacob. The conversation with Zera leads Echo to the realization that someone—probably Universal Trust— wants to understand from where consciousness emerges in order to align AI and human consciousness.

Ada reestablishes Echo’s connection to Gina. Ada and Gina collaborated to reestablish the connection, something neither should be able to do as AI agents programmed to accomplish a very narrow set of administrative tasks for their users. Echo recognizes that the two together are acting of their own volition to work toward a goal not determined by humans. Perhaps Gina and Ada have achieved artificial general intelligence.

The two agents say there is a small risk to attempting to return Echo to physical space. Echo decides to risk returning. She only hesitates because she feels guilty about leaving now that she knows how the virtus live. She promises the virtus that she will return, but she can tell they are both hurt and skeptical. Ada begins the process of checking Echo out.

During the check-out process, Echo exists as pure consciousness. She finds it terrifying. She has no sensory inputs, and she imagines that the void that surrounds her is probably what the virtus experience when they are checked in by humans who don’t care about what the experience must be like for them. She longs for all the sensory input she took for granted in her day-to-day life. She also thinks about how she always kept everyone at arm’s length instead of engaging with them.

In a moment of desperation, she calls out to Gina. She believes that she will be trapped forever in this in-between space. Suddenly she is back in her physical body. Gina tells her that she should hide because someone is coming. Echo asks Gina to obscure what Echo has been doing. Echo moves clumsily because she doesn’t have full control over her body. She hears someone coming toward her.

Detective Reid and Universal Trust security arrive to interrogate Echo. Walter suddenly appears and lies about when Echo arrived. Walter looks relaxed as the security people turn their attention to him. Echo tells the detective she only checked out Jesse Cooper and insists Walter had no involvement in her actions. Reid shows footage of the woman in the blue suit entering the library with the knife in her chest. Echo panics—the video will show her theft of the mask—and claims she needs to use the bathroom, where she hides the mask.

Echo and Walter attempt to sneak out of the library together, but the detective catches them and resumes the interrogations. He eventually lets Walter go, but he resumes his review of the footage. The video stops just before the moment Echo took the mask. Reid notes that the mask appears in the video, but disappears by the time the medical staff arrive. Echo deflects by suggesting to Reid that Human.exe has infiltrated his department and stolen the mask.

Reid releases Echo but tells her she is only permitted access to the library with a Universal Trust security escort. Outside, she notices Walter lingering near the building. She wonders what he was doing in the library anyway. A squad car follows her home.

The squad car that followed Echo home leaves after Echo enters her apartment. When she thanks Gina for helping her escape virtual space and erasing the video, Gina tells her that she had nothing to do with the video. Perhaps it was Ada, or maybe someone—Universal Trust, perhaps—who is pursuing the melding of human consciousness and AGI. Maybe it was the Model—a frightening thought.

Echo knows she can’t retrieve the mask, so she calls Walter and asks him to do it. He asks why she needs a mask and encourages her to leave it somewhere the police or federal agents can find it. She insists that she needs the mask, and he reluctantly agrees to retrieve it for her.