As Jay drifts toward unconsciousness, he hears a voice that he recognizes as Mitt’s, saying, “Well done.” Jay realizes that he has managed to save himself without help. A surge of gratitude for the giant squid beak washes over him, and he kisses the object before naming it “Beaky.”

The act of naming the beak unlocks a long-suppressed memory. In the darkness, Jay decides to explore this memory, hoping that it might help him to survive.

The narrative enters a flashback to 2014 and is set in a young Jay’s bedroom. Jay is crying as Mitt counsels him on how to deal with teachers, whom he calls predators. Mitt systematically lists and dismisses four typical survival options available to prey, stating that it is possible to either accept the predation, team up with allies, build up a strong defensive method, or camouflage oneself. Mitt rejects these four methods.

His demeanor shifts as he describes his preferred fifth option. Mitt tells his son that the prey must become so dangerous and unpredictable that predators will choose to leave it alone.

In the present, Jay remembers that when whales are distressed, they can regurgitate their stomach contents. He plans to stab the stomach wall with Beaky to induce vomiting. The hallucinatory voice of Mitt protests this plan, but Jay argues with the voice and resolves to proceed.

Suddenly, the whale’s gullet opens, and a shower of freshly eaten fish rains down. The Mitt-voice asks if Jay had not assumed that his father would always be there for him.

Jay laments the lost opportunity for a final confrontation with Mitt. Now, he and the Mitt-voice argue about control. The voice states that a whale cannot see what is directly in front of it. Jay interprets this to mean that Mitt is making an excuse for his past negligence by claiming that obsessive people ignore their loved ones.

Rejecting this idea, Jay lifts Beaky to stab the stomach wall. As he tenses, the Mitt-voice screams at him not to do it.

In a flashback to Christmas Day, 2021, Jay visits Mitt’s gravesite with his mother, grandmother, and sister. Overwhelmed with guilt for his choice to remain absent during his father’s long illness, he now resolves to perform a brave act to show his remorse.

He observes the domed dirt over several new graves nearby, which makes him think about the topic of pressure. He concludes that when things are pulled taut, a person must be willing to make the cut.

In the present, Jay ignores the voice and stabs the whale’s stomach wall. The stomach clenches violently in response, launching him across the chamber. The impact knocks his regulator out, and he swallows a mouthful of blood and seawater.

His plan has backfired. Instead of vomiting, the frightened whale begins a deep, powerful dive, and as the pressure on his body mounts, Jay realizes that he has made his situation worse.

A quick succession of flashbacks illustrates Jay’s personal history of falling. In 2014, his grandmother shoves him off a porch. In 2015, he falls from a dock. In 2016, he falls off his bike. In 2017, he falls off the honor roll.

By 2018, his obsession with diving causes him to fall off his friends’ radar. In 2019, he feels lost without his father as a compass. The montage ends in 2020, with a 15-year-old Jay leaving home, determined to rebuild his life.

As the whale continues its dive, the immense external pressure slams Jay against the back wall of the stomach. The voice of Mitt provides fatalistic data about the increasing depth. Jay feels immense regret for how he treated his family and resigns himself to death.

His body begins to shut down, and his lungs contract. He stops fighting and decides to choose his final thought.

For his final thought, Jay chooses a memory from July 4, 2021, five weeks before Mitt died. In this memory, he is on a beach with his mother, watching fireworks. She tells him, “You don’t look anything like him” (182), a comment that he interprets as having a double meaning. The fireworks illuminate the tears on his face.

In the present, Jay decides that this is a memory he can die with.

As the pressure intensifies, Jay experiences nitrogen narcosis and feels a sudden euphoria. He feels as though his skull is being pulled apart, and his right eardrum suddenly implodes. Despite the physical trauma, he feels strangely calm as he tastes the bitter flavor of his collapsing lungs.

The ruptured eardrum destroys Jay’s equilibrium. He has an epiphany, realizing that his lifelong conflict with Mitt was rooted in their impatient nature, and he realizes that this shared trait caused them not to realize more fundamental truths about their relationship. Jay finally understands his father’s philosophy: A person must learn to appreciate the world’s tiniest details in order to comprehend the infinite.

Jay communicates with his father’s hallucinatory voice; they both exchange apologies and regrets. The voice comforts Jay, telling him that he is going home. Jay then experiences an intense pressure against his mask as the extreme depth compresses the mask against his face. He understands that his body is about to be destroyed, but his father’s voice comforts him.

As his mind unravels, Jay develops a theory that whales are psychopomps—creatures that guide souls to the afterlife. He speculates that they must absorb the souls of beings that die in the ocean, then ferry those souls between worlds. He connects this idea to a “SAVE THE WHALES” mug that his father once owned, and he concludes that when people die, whales save them. He drifts peacefully as his other eardrum ruptures.

A series of short chapters includes fragments of positive memories that reveal Mitt’s kinder side. In 2014, he and his father discuss the nature of happiness. In 2010, Mitt points out a series of constellations to his children. In 2012, Mitt lets Jay “drive” a dump truck. After a bad haircut in 2014, Mitt gives Jay his favorite cap.

Other memories include the family singing “Free Fallin’” together in 2015, Mitt sharing food with a homeless man in 2017, and Mitt playfully making Jay laugh during a downpour in 2018.

Jay feels remorse for having lost sight of these positive memories. Suddenly, the whale’s deep dive comes to a violent halt. He feels a massive rush of frigid water as something enormous passes by in the darkness.

The whale’s sudden stop throws Jay forward. A loud impact strikes the whale, shoving Jay again. The whale thrashes in panic. Jay holds onto the stomach wall and realizes that the sperm whale is being attacked by its only natural predator: a pod of orcas.

A flashback takes Jay back to a whale-watching trip in 2014. In this memory, Mitt’s friend, Hewey, identifies an attacking pod of orcas and calls them the bringers of death. A nine-year-old Jay and his father watch for two hours as the orcas, which Hewey labels the wolf packs of the sea, attack and kill a gray whale. The prolonged spectacle leaves Jay traumatized.

In the present, multiple orca impacts strike the sperm whale, and its heartbeat becomes erratic. The whale’s gullet opens, flooding the stomach with its own blood. The blood coats Jay’s mask and fills his mouth. Trapped inside, Jay is forced to witness the whale being killed.

Jay deduces that the orcas are attacking the sperm whale because it is old and wounded. He draws a parallel between the whale’s vulnerability and Mitt’s weakness in his final days. As Jay realizes that his survival is now tied to the whale’s, his personal fight expands to include a broader fight for the whale’s life.

In a flashback to 2016, Jay sits in a truck with Mitt, who has just been fired from his most recent job. Mitt tells Jay that people should learn benevolence from whales. He explains that whales in Monterey Bay are known to protect other species. Jay recalls a biologist’s story of a humpback whale saving her from a tiger shark.

Jay internally urges the injured whale to fight back. The Mitt-voice informs Jay that the whale’s tail is ripped, so it cannot flee. Jay tells the whale to call for help, but the voice replies, “We are male” (204), explaining that adult male sperm whales are solitary. Desperate, Jay presses his lips to the stomach wall and begs the whale to call out anyway.

The sperm whale endures repeated blows from the orcas, and Jay perceives that it has given up and is passively accepting death. The whale’s surrender reminds him of his father’s death by suicide, and he compares the whale’s current state to Mitt’s decision to tip himself out of his rowboat.

The whale suddenly emits a series of deafeningly loud click codas, sending a distress call. The orca attack abruptly stops, and an armada of female sperm whales arrives to help. The females shield the injured male, pushing him through the water. The Mitt-voice says the word “Star,” and Jay realizes that the pod is forming a “marguerite”: a star-shaped defensive formation.

Jay recalls Mitt and Hewey describing the marguerite formation and understands that his whale is now protected. The mention of stars prompts Jay to remember the traumatic night on the boat, when his father tried to force him to cut himself. He realizes that the stars he saw that night illuminated his desperate swim back to shore, ensuring his survival.

Jay intuits the remainder of the battle as the sperm whale pod repels the orcas. The formation loosens, and the sperm whales begin a slow ascent with the injured male. As the pressure lessens, Jay feels some relief. The stomach is now half-filled with blood. Feeling that the whale is safe with its family, he presses his hand against the stomach wall in solidarity.

As the pod ascends, the injured whale instinctively feeds. Water, fish, and a helmet jellyfish spill into the stomach. As the jellyfish dies, it emits a bright red bioluminescent light, which Jay perceives as a gift of hope.

Jay worries about getting the bends from ascending too quickly, but he notes that the whale’s ascent is slow. He inspects the stomach’s contents and scrapes his hip on a sharp chunk of concrete. Wondering why a whale would swallow concrete, he concludes that it may have done so deliberately, using the object as a weight.

In a flashback to Mitt’s funeral, Jay asks Hewey how his father managed to weigh himself down. Hewey replies, “Dive weights.” Jay connects his father’s method to suicides described in Cannery Row and to the behavior of whales that sometimes swallow rocks to weigh themselves down.

In a flashback to the previous day at a dive center, a clerk recognizes Jay as Mitt’s son. She recounts how Mitt once saved her life during a dive when he noticed that she was carrying a dangerous number of weights. She tells Jay that many people in the community have similar stories about Mitt’s legendary status as a diver. For the first time, Jay realizes that his own view of his father may have been incomplete.

The escort pod departs, leaving the injured male to die alone. Jay checks his gauge and sees that less than a third of his air is left. He assesses his extensive injuries and reflects that he and his father are now witnessing each other’s deaths. Thinking back on the last words that Mitt ever said to him, he concludes that a son’s ultimate “responsibility” is to hold his father “accountable.”

Jay confronts the Mitt-voice, accusing his father of treating him like a “servant” while adoring his sisters. In the ensuing conversation, Jay asks his father many questions, lamenting that life could have been so different if Mitt had not made certain choices. He asks if the whale ate Mitt’s body, then deliberately insults his father’s weakness and his choice to die by suicide. The voice screams “WHERE ARE YOU?” before responding with a deafening sonic blast that causes Jay intense pain.

A montage from 2021 details the progression of Mitt’s terminal illness and Jay’s avoidance of his family crisis. In a series of back-to-back scenes separated by weeks or months, Jay deletes a voicemail from his mom, sends a heart-emoji response to a concerned text from his sister, Nan, and makes an excuse to end a FaceTime call with his other sister, Eva. Later, he zones out during a call as his mom describes Mitt’s major surgery. The sequence ends with Jay archiving a frantic email from Nan, who states that Mitt is asking for Jay and demands, “When he says DON'T BREAK MY HEART who could he be talking about JAY” (230).

In the present, Jay apologizes to the Mitt-voice, which tells him that although there is no time for apologies, strength remains. Encouraged, Jay resolves to fight. The voice prompts him to remember the last thing he saw before being swallowed. Jay recalls two trident-shaped symbols on the whale’s throat and realizes that they were claw marks from an escaped seal. He concludes that if a seal could get out, so can he.

Jay methodically prepares for his climb. He streamlines his gear, removing spare batteries and tucking away hoses. He checks his console, which reads that he is at a depth of 70 feet and has 863 psi of air. He leaves the console accessible, then uses Beaky to cut the empty bone bag free.

Jay determines that the gullet sphincter is too strong to force open, but he is reluctant to cut the dying whale again. The Mitt-voice insists that doing so is necessary. When Jay refuses, the voice goads him with a cruel insult from his past, stating, “YOU GOT SOFT LUNGS JAY” (236).

Angered, Jay furiously uses Beaky to cut at the gullet sphincter. He saws a pie-shaped piece of the muscle loose, creating an opening, then taunts his father’s memory by asking aloud if his lungs sound soft now. He carefully puts Beaky away in a pocket.

Jay realizes that he needs a light source to navigate the dark gullet. He sees the dormant helmet jellyfish and knows that he must touch it to activate its bioluminescence, despite the risk of being stung. He cautiously nudges the jellyfish with a knuckle, and it blazes with bright white light. Realizing that he must hold it to use it as a lantern, he forms a plan.