An unnamed narrator receives three notebooks and photographs of a troubled man from a bar proprietress.

Yozo Oba grows up in a wealthy household secretly paralyzed by a deep fear of other people.

Unable to connect with others, Yozo crafts a clownish persona to keep people at a safe distance.

A classmate named Takeichi suspects Yozo deliberately faked a fall during gym class to get laughs.

Horiki Masao introduces Yozo to alcohol, prostitutes, and left-wing politics during his university years in Tokyo.

Yozo becomes head of the student Marxist groups in Central Tokyo, doubling his responsibilities and despair.

Yozo and Tsuneko throw themselves into the sea; she drowns while he is rescued.

Expelled from university and disowned by his family, Yozo moves in with Flatfish and lives on a secret allowance.

Yozo moves in with Shizuko, becomes a children's magazine cartoonist, and acts as a father figure to her daughter.

After a drinking relapse, Yozo abandons Shizuko and moves in with the madame of a Kyobashi bar.

Yozo marries Yoshiko, a young tobacco shop girl, after promising to quit drinking, then immediately relapses.

Horiki leads Yozo to a window where Yozo watches Yoshiko being raped by a neighborhood shopkeeper.

Yozo swallows a bottle of sleeping pills with gin in a second attempt to die by suicide.

Flatfish and Horiki commit Yozo to a mental institution, where he concludes he has ceased to be human.

The bar madame tells the narrator that despite everything, Yozo was a good boy and an angel.

Yozo Oba grows up secretly terrified of human beings, hiding behind a clownish persona to survive social life. After a fellow student nearly exposes his act, Yozo falls deeper into dissipation through drinking, Marxist politics, and a doomed relationship with Tsuneko that ends in a suicide attempt. Surviving while Tsuneko drowns, Yozo is expelled and disowned, drifting through life as a kept man with Shizuko before abandoning her for a bar madame's hospitality. His marriage to the trusting Yoshiko offers brief stability, but witnessing her rape destroys him, leading to a second suicide attempt and morphine addiction. Flatfish and Horiki ultimately commit Yozo to a mental institution, completing his sense of being disqualified from humanity. In a final irony revealed through the novel's frame narrative, the woman who knew him best remembers Yozo not as a monster but as an angel.

The core arc of Yozo's descent from isolation to ruin.

A maidservant commits a secret abuse against young Yozo, which he never reports and which haunts him into adulthood.

Yozo's natural intelligence and humor endear him to teachers, shielding him from punishment despite rarely attending classes.

Unable to voice his wishes aloud, Yozo sneaks into his father's office at night and writes 'lion mask' in a notebook.

Takeichi shows Yozo a Van Gogh print and calls it a picture of ghosts, igniting Yozo's desire to paint.

Yozo begins painting ghost self-portraits that expose his true inner self, shown only to Takeichi and hidden from everyone else.

Yozo's father enrolls him in university to become a civil servant rather than the artist Yozo secretly wants to be.

Yozo fabricates a lung illness to escape dormitory life and move into his father's Tokyo townhouse.

Horiki refuses to kiss Tsuneko at her bar because her poverty-stricken appearance disgusts him.

During his cross-examination, Yozo fakes some coughs during a genuine coughing fit, and the prosecutor's question haunts him for years.

Flatfish indirectly offers Yozo a chance to rebuild his life, but Yozo fails to understand the conditional offer.

Shigeko, the daughter Yozo has been caring for, innocently tells him she would ask God to bring back her real father.

Yozo steals some of Shizuko's clothes to pawn for drinking money and disappears on a multi-day bender.

Yozo drunkenly falls into a manhole, and Yoshiko, a local tobacco shop girl, helps pull him out.

Returning to Tokyo from a failed recuperation at a hot spring resort, Yozo vomits blood in the snow.

After his release from the institution, Yozo's brothers arrange for him to live in a remote coastal house with an older servant.

Behind the headline events of Yozo's life lies a series of quieter but equally devastating moments that explain how he became who he was. A childhood abuse by a maidservant and an inability to express his own desires leave lasting scars, while his natural intelligence and humor allow him to hide his suffering in plain sight. His passion for art is sparked by a classmate's offhand remark about ghost paintings, yet this dream is immediately denied when his father dictates his future. The practical humiliations mount — faking illness to escape university dormitories, pawning belongings, falling into manholes drunk — as Yozo's life unravels at the seams. Small emotional turning points, like a surrogate daughter's innocent wish for her real father or a failed offer of help from Flatfish, quietly deepen Yozo's shame and self-loathing. By the novel's end, he has been relocated to a remote coastal house where even his final act of agency — purchasing sleeping pills — fails him completely.

The hidden wounds and quiet moments that shaped Yozo's fate.

The unnamed narrator describes three photographs of a man as subtly repulsive, as if something inhuman lurks beneath the surface.

Yozo realizes he has never understood how other human beings find happiness and feels entirely sealed off from the rest of humanity.

Takeichi predicts that many women will fall for Yozo, a prophecy that horrifies and haunts Yozo for the rest of his life.

Yozo discovers that alcohol briefly liberates him from his terror of other human beings and begins drinking heavily.

Yozo's father retires from politics and sells his Tokyo townhouse, plunging Yozo into financial ruin.

Tsuneko confesses her deep unhappiness to Yozo during a night together, giving him a rare feeling of true contentment.

Yozo is charged as an accomplice to Tsuneko's suicide and contacts his father's associate Flatfish to act as his guarantor.

Yozo flees Flatfish's house with a note saying he will return, but instead goes straight to Horiki's apartment.

Yozo, Shizuko, Flatfish, and Horiki formally agree to sever all ties between Yozo and his family.

After Horiki warns Yozo about womanizing, Yozo concludes that society is just an individual and grows temporarily bolder.

After watching Yoshiko's rape without intervening, Yozo's hair turns prematurely gray and he sinks into hopeless alcoholism.

Yozo wakes from his second suicide attempt to find Flatfish and the bar madame attending his bedside.

Before being taken away, Yoshiko offers Yozo morphine and a syringe; for the first time in his life, Yozo refuses.

Yozo realizes the facility he was taken to is a mental institution and accepts the label of madman.

Released from the institution and told of his father's death, Yozo ends his narrative aged beyond recognition at just 27.

At key moments throughout Yozo's life, realizations and revelations shift the course of his story in ways he cannot recover from. A classmate's prophecy about women haunts him from high school onward, while the discovery that alcohol dulls his terror of humanity opens the door to lifelong addiction. The suicide attempt with Tsuneko marks his first legal disgrace, and his subsequent wandering — fleeing Flatfish, formally cutting ties with his family — shows how completely he surrenders control of his own life. Witnessing Yoshiko's rape shatters the one thing Yozo trusted — her unconditional faith in others — and the moment his hair turns gray signals how completely that event breaks him. His refusal of morphine before being committed is the only moment in the novel where he says no to something offered to him, a tiny flash of agency in a life defined by helplessness. Released from the institution and told of his father's death, Yozo ends his narrative at just 27 years old, aged beyond recognition and certain he has forfeited his place among human beings.