A week after their engagement, the apartment is filled with flowers and celebratory gifts from Peter’s friends and family. Joseph, however, hasn’t told anyone yet. He knows he should start by telling Lena, but she will ask him if he is “sure” about the marriage, and he doesn’t “know how to answer” (175). He has promised Peter that they will visit Uncle Luke, Joseph’s only blood relative in New York, to share the news, but at the last minute, Joseph decides he should see his uncle by himself. Peter doesn’t argue, and Joseph thinks about the many secrets he keeps from his fiancée.

Uncle Luke lives in a large, old house in Cobble Hill, one of the remaining vestiges of Joseph’s family’s former wealth. He doesn’t speak, but communicates in grunts and by writing on a pad with his “gnarled” fingers. He asks about M, and Joseph tells him he is still in Berlin with Magos. After the operation on his arm-tail, Monstrilio slowly transformed into a boy. Now, a patch of fur on his forehead and his sharp fangs are the only visible remnants of his former life. However, he is still “shy” and “unsure of his new body” (178). Magos calls him “Santiago” now, but Joseph knows that M is someone different.

During the summers, M comes to stay in Cobble Hill, and he and Uncle Luke share a special bond. Once, Joseph caught M eating live crows in the backyard. He rushed to stop him, determined “to weed out whichever Monstrilian instincts remained in M” (178), but Uncle Luke disapproved, feeling M was “incredible” just the way he was.

After Lucía’s death in Mexico City, Magos received a performance art opportunity in Berlin, which she felt would provide M with a “fresh start.” However, to date, M has shown no signs of adapting to his new life and has refused to leave the apartment.

Joseph changes the subject to tell Uncle Luke about his engagement. He asks if he will tell Peter about M. Joseph isn’t sure. He is afraid of Peter learning the truth about M, but he also “still [isn’t] sure [him]self” (181) exactly what happened or how to explain the situation. Uncle Luke grunts that he shouldn’t tell Peter.

After Peter leaves for work, Joseph calls Berlin to wish M a happy birthday on the day they used to celebrate Santiago’s birthday. He tells Joseph he was knitting and that he finished reading Julio Cortázar’s Bestiario (1951). These are things that Santiago never did, and it helps Joseph “separate” M from his dead son. However, in other moments, Santiago’s memories resurface in M, such as in his craving for Fruit Loops.

M tells Joseph that Magos got him a job as an assistant at a gallery. He will “have to practice going outside” (184), but Joseph promises him he will do great. He summons his courage to tell M about his engagement, but then Magos gets on the phone.

Magos tells Joseph that her new project isn’t going well and asks him how Peter touches him, if he likes to “grab or caress” (186). Joseph remembers how Magos used to touch him, exploring his body when she thought he was sleeping. After hanging up, Joseph tries to think about nothing except the day ahead, pushing all “decisions or uncertain futures” (187) firmly out of his mind.

A month into their engagement, the owner of the corner bodega, the wine-store owner, and two Trader Joe’s cashiers know that Peter and Joseph are getting married, but Joseph still hasn’t told anyone but Uncle Luke. Things are going well for M and Magos in Berlin; there is no reason for Joseph to fear that his secrets will be exposed. Finally, he texts Lena, asking her to meet him for a beer.

Joseph and Lena meet in a bar in Greenpoint. The bartender knows Lena and brings them bourbon along with their beers. Lena is surprised by Joseph’s news and asks why he is afraid to tell Magos. She tells him Magos is “calmer” and “more centered;” they talk often about her life in Berlin, the performance piece she is working on, their neighbor who has a crush on M, and the neighbor’s cat that drops in to visit. Both Magos and M love the cat, and Joseph insists that M knows better than to eat the creature now.

Lena doubts that M is doing as well as Joseph thinks. Joseph tells her that M is enjoying his job and that he has a crush on his boss, Thomas, which seems encouragingly “human” to Joseph. Lena accuses him of being “in Magos’s camp” (194), Joseph counters that he doesn’t think M is Santiago but still believes “he has a right to be human” (194). Lena asks if he has told Peter about M. Joseph doesn’t know how and feels that keeping the secret is “safer.”

M calls Joseph late one night to tell him he had sex with Thomas. M looks “anxious” as he tells him that Thomas didn’t think the “stump” where his arm-tail used to be was “ugly.” They got naked, and the smell of sex made M “happy dizzy” and “hungry.” His eyes betray “soft joy” but also fear as he tells Joseph that he couldn’t help biting Thomas. At first, Thomas was angry, but M apologized and promised not to bite him again. Joseph can hear the “heartbreak in his voice” (197). He is torn between the hope that M’s “hunger” will go away and the fear that losing his “Monstrilioness” would leave him “empty.” He wants to be “strong enough” to set M “free,” but instead, he tells him to get some rest and go to bed.

After the phone call, Joseph goes down to the piers and watches a tourist boat making its way back from Governors Island. He imagines the boat filled with children and an unexpected whirlwind capsizing it. The parents wouldn’t believe their children were dead. They would sue the boat company and the school, and form support groups in search of “closure,” but what they really needed was “escape.” Peter calls, interrupting Joseph’s reverie, telling him he has to come home immediately to deal with a “situation.”

Joseph hurries home in a panic, terrified that Peter has found out the truth about M. He thinks that he should have done more to “celebrate” M’s “steps into humanhood” (199), instead of “scolding” him when he went astray, and wonders if M or Magos designed to tell Peter as some kind of payback.

Joseph finds Peter in their apartment, hiding from a giant tarantula climbing up the wall. Joseph is giddy with relief. Peter screams at him to kill the creature, but Joseph approaches it with curiosity. He can tell it is “bewildered” and gently coaxes it into a yogurt container. As Peter shelters under a blanket, Joseph takes the spider to a park near the river and releases it.

After dinner, Peter initiates sex with Joseph. Joseph kisses him harder than usual, tearing his shirt open and pinching his nipples so hard that Peter complains. He kisses Peter’s stomach and is overcome by a sudden urge to bite him. He sinks his teeth in, biting harder even as Peter demands that he stop. He finds “an exhilarating power” in the forbidden action (205). Peter shoves him away, angry, but forgives Joseph when he apologizes.

Joseph, Peter, and Lena travel to Berlin for the premiere of Magos’s new show, a piece called Son. Peter is thrilled at the opportunity to spend more time with Joseph’s family, but Joseph is apprehensive. At dinner, Peter announces their engagement, causing M to lapse into a coughing spell. Magos moves to help him like she would have when Santiago struggled to breathe, but M doesn’t need her help.

The next day, M and Thomas, now his boyfriend, show Peter and Joseph around Berlin with Magos and Lena tagging along. Lena tells Joseph that Magos “made some sort of declaration to her” (211), which she “rejected” but agreed to stay in Berlin a little longer. Peter tries to make conversation with M, but rarely receives more than a single-word response. Only M’s fangs, filed down to dull the points, are the only indication he isn’t “a regular young man” (212). At the Holocaust Memorial, M and Joseph wait outside for the others. M tells Joseph that he likes Berlin and is glad his father is happy with Peter.

After the memorial, Peter, Joseph, M, and Thomas drink beer in the sun. M tells them about his work at the gallery, and Joseph wonders if this “sanitized version” of M is truly better (214). A bumblebee lands on the rim of M’s glass, and he swallows the creature without hesitation. Only Joseph sees.

M leaves the table suddenly to walk down the street, and Joseph catches up with him. He tells Joseph that he “got bored” and asks how to “make sure people don’t stop liking you” (215). Joseph suggests that you can only try your best not to hurt them, and M asks if one way to do this is by “not eating them” (215). Joseph can tell this is M’s attempt at a joke.

Peter, Joseph, Lena, M, and Thomas meet outside a warehouse for Magos’s performance. As they head inside, M asks Joseph if he still misses Santiago. Joseph admits that he does, and M tells him that Magos does, too.

As the show begins, Magos walks on stage in a nightgown. She unwraps a fabric parcel on the floor to reveal a set of dinosaur pajamas, the same ones that Santiago died in. She holds the pajamas in her lap and proceeds to cry, sobbing openly as she never had when Santiago died. Soon, the audience is crying too, as Magos becomes more and more “disheveled” from her grief. Lena covers her mouth with a hand, and Thomas cries, but Peter just looks confused. M looks straight ahead, rubbing the stump where his arm-tail used to be as he watches Magos “mourn the child she had been grooming him to replace” (220). Joseph cries tears he has “earned,” but he desperately wants Magos to stop her show.

M slips out of the warehouse. Joseph tries to follow him, but loses sight of him in the crowd. As the show ends, the rest of their party meets Joseph outside. Joseph is worried that M might “do something,” but Lena assures him that M just needs some space. Nevertheless, Joseph asks Thomas to go look for M.

The reception starts, and Magos makes her way over to her family, eager to know what they thought of the show. Lena tells her it was “fucking horrible,” and Joseph demands an explanation. When she learns that M is missing, Magos’s “smug brightness” disappears. She insists that the show “had nothing to do with him” (224), which Joseph finds ridiculous, after she has been referring to M as Santiago for years. Magos is dragged away to meet her admirers, and Peter demands that Joseph tell him what is really going on. Joseph cannot, and Peter returns to their hotel alone.

When M still hasn’t reappeared after the reception, Lena, Magos, and Joseph go for a drink, momentarily forgetting their troubles and feeling as if they are university friends again. Back at Magos’s apartment, they find the neighbor’s door standing open. Magos peeks inside, calling the neighbor’s name, but there is no reply.

Inside, they find M naked and covered in blood. He is curled in a ball and doesn’t respond to Joseph’s frantic calls. The neighbor is also naked and covered in blood. He is alive, but barely. Joseph is in a shocked daze, so Lena and Magos take control of the situation. They call an ambulance, and Joseph hurries M away to Magos’s apartment, where he bathes him and packs hurriedly. Joseph realizes he is also covered in blood. He washes and changes quickly and puts all their bloody clothes in the laundry.

Sirens announce the arrival of the ambulance. Joseph hears the commotion in the neighboring apartment and prepares to defend M. No one comes to the door. Upon hearing the paramedics carrying the neighbor away, Joseph takes M and hurries him out of the apartment.

Joseph and M walk toward Joseph’s hotel. Joseph imagines how the night could unfold. He imagines Peter discovering and accusing M of murder, or M eating Peter. When Santiago was young, Joseph used to imagine what the future would be like, what he would be like as an adult, but his current reality is past all imagining.

At the hotel, Joseph urges a half-awake Peter to keep sleeping as he helps M make a “nest” on the floor. Joseph struggles to sleep. He can hear M whimpering and remembers how he had longed for M’s arm-tail to grow back after the amputation, swearing that he “would accept [M] for what he was” and “wouldn’t judge his hunger” (240). Now, with no arm-tail but the same insatiable hunger, Joseph wonders how much of this promise he is still “responsible for.”

In the morning, Joseph texts Magos that he will bring M back to New York with him. She agrees with his plan. She and Lena have spent the night at the hospital with the neighbor, who is barely alive. When Peter wakes, Joseph insists that everything is fine, M just needs a break from Berlin. Peter remains suspicious.

When M wakes, he tells Joseph that he wants to apologize to the neighbor. Even though M was “super hungry” and the neighbor was “very delicious,” he had forced himself to stop eating and not kill him. He doesn’t want to leave Berlin, Thomas, and his job at the gallery. M asks if Joseph has told Peter about when he was Monstrilio. Joseph tells him Peter “wouldn’t understand,” but when M asks if Joseph understands, he has no answer to M’s “wild and confused” eyes (244).