In May 1938, the narrator, Aoyama, arrives in Taichū and is immediately overwhelmed by Kanjō Bridge Avenue, a market district whose parade of unfamiliar goods and languages recalls a magic troupe procession she once witnessed in Nagasaki as a child with her Aunt Kikuko.

Through flashbacks, Aoyama explains how she came to be in Taiwan. After her the film adaptation of her novel A Record of Youth succeeded at the box office, a magazine editor offered to fund a South Pacific trip in exchange for serialized propaganda supporting the Southern Expansion Policy. Aoyama refused, but the exchange lodged Taiwan in her imagination. Unable to afford an extended stay independently, she appealed without success to her aunt. Her funding problem was solved when the Nisshinkai women’s organization and the Government-General of Taiwan issued a joint invitation covering all costs, motivated by the warm reception her film A Record of Youth had received from Taiwanese audiences.

Aoyama travels to Taichū on her own, buying food from platform vendors along the way. She asks a ticket collector where Islanders shop and is directed to Kanjō Bridge Avenue. While attempting to buy an unfamiliar fruit from a young vendor, she becomes entangled in a miscommunication over packaging. A petite young woman with dimples resolves the confusion in flawless Japanese. The vendor expresses gratitude by giving Aoyama a packet of kue-tsí (small roasted seeds). The woman demonstrates how to bite through the shell to reach the edible kernel inside. At that moment, Mishima Aizō, a Taichū City Hall staffer, arrives for their 2 pm meeting, which Aoyama has entirely forgotten. She is taken away by taxi, and the young woman quietly disappears.

At the Takada residence in Muhō, Aoyama meets members of the Nisshinkai before attending a lavish banquet at a Mainlander-oriented restaurant. Though the food is impressive, it is nothing like the authentic Taiwanese street food Aoyama craves. Mishima deflects every request; Aoyama’s host, Madame Takada, later reveals Mishima was once blamed when Mainlander guests fell ill from a local clam dish, noting that only an Islander could properly judge its quality. As a remedy, Madame Takada has engaged a female Islander interpreter to guide Aoyama: Ō Chizuru, a former Japanese-language schoolteacher. Aoyama rushes to the waiting room and immediately recognizes Chizuru as the woman from the market. Chizuru explains she identified Aoyama at the fruit stand and heard about the interpreter position through her sister. She promises to take Aoyama to the market that afternoon for the Taiwanese foods she has been longing to try, and gives her another lesson in eating kue-tsí.

Aoyama sits with Chizuru, whom she privately nicknames “Chi-chan,” taking notes while Chi-chan explains Taiwan’s railway network and the 1935 Great Shinchiku-Taichū Earthquake, which destroyed the renowned Gyotōhei Bridge. Chi-chan also walks her through Taiwan’s ethnic landscape: the Hoklo majority who speak Taiwanese (Hokkien), the Hakka minority with their own distinct dialect, and numerous indigenous tribes, each with separate languages and traditions. When Aoyama asks about Chi-chan’s own heritage, Chi-chan gives a carefully answer expressing imperialist sentiments before confirming that her family is Hoklo.

In June, during the rainy season, Aoyama moves from the Takada residence into a compact one-story Japanese-style cottage beside the Yana River, provided rent-free by Madame Takada. Chi-chan begins visiting twice a week and, well beyond her role as interpreter, arranges climate-appropriate clothing, a library card, bus maps, and a list of suitable restaurants for Aoyama, all before Aoyama has thought to ask for them.

When Chi-chan accompanies Aoyama to a lecture at her own former girls’ high school, a male staff member treats Chi-chan as domestic help and orders her to clean Aoyama’s shoes. Aoyama publicly corrects him, identifying Chi-chan as her interpreter. She later complains about the incident to I-san, a university administrator, only to learn that he had sent Chi-chan home from a university event, seeing her presence as unnecessary. I-san justifies this by noting that Chi-chan is merely a privately hired Islander interpreter from a public school. Furious, Aoyama declines an invitation to a luncheon and returns to the cottage to find Chi-chan there with savory bí-thai-bàk (rice noodles in pork bone broth). Chi-chan had prepared it on the assumption that Aoyama would not enjoy the formal meal. Aoyama finishes the entire pot.

Afterward, Aoyama speaks candidly about her opposition to war propaganda and the social pressure to marry, then formally asks Chi-chan to be her friend. When the rain clears, they sit on the veranda eating lychee while Aoyama explains her philosophy that true travel means living through all four seasons in a foreign place, not rushing between designated sights. She reveals plans to remain in Taiwan a full year and eventually publish a book titled Taiwan Travelogue. Chi-chan supports this, in contrast to cautionary telegrams from Aoyama’s Aunt Kikuko. The chapter ends with Aoyama, struck by Chi-chan’s effortless command of classical quotation and her unreadable composure. Aoyama asks for the privilege of calling her “Chi-chan” aloud.

In Shōka, Aoyama and Chi-chan attend a screening of A Record of Youth followed by a formal banquet, at which Aoyama has no time or space to eat. Chi-chan later leads her to street food on Shōsei Street afterward. In a tearoom, Aoyama fails repeatedly to identify Chi-chan’s professional ambitions.

Two young women, distantly related to Chi-chan, enter the tearoom and direct contemptuous remarks at her in Taiwanese, invoking the term “muâ-inn-thng.” Aoyama confronts them until they leave. When Chi-chan offers to find a replacement interpreter rather than explain, Aoyama insists she is asking as a friend, not scrutinizing her credentials.

While exploring the ancient town of Rokkō, Chi-chan discloses her background. The Ō family are wealthy, long-established Hoklo landowners in Taichū. Chi-chan is the daughter of a concubine whose mother had been a gē-tòa, an entertainer akin to a geisha. Neglected and at times hungry, Chi-chan was sent as a child to live with her mother’s impoverished jute-farming relatives, the origin of the slur “muâ-inn-thng.” She was eventually taken back into favor by a half-sister and is now engaged to a Mainland-educated man, an arrangement her father and sister secured to spare her the worst fates typical of concubines’ daughters.

Aoyama finds this outcome unjust; Chi-chan views it pragmatically as the best available path for someone like herself. Aoyama correctly deduces that the same half-sister arranged the interpreter position to expose Chi-chan to Mainland customs before her wedding. At Aoyama’s request, Chi-chan begins addressing her as “Aoyama-san.”

On the train station platform, Chi-chan confides that her one shared meal with her fiancé was soured by thoughts of the structural inequality in arranged marriages. She doesn’t know of any writer who has captured what women actually feel in such circumstances. Aoyama declares she ought to write a novel for Chi-chan.

On the train home, Chi-chan reads a Han-language novel Aoyama bought her. At Aoyama’s request, she translates aloud a fantastical story about quarreling Taiwanese gods. Listening to Chi-chan’s measured, clear narration, Aoyama suddenly grasps Chi-chan’s true ambition: to become a professional literary translator. A rare brightness in Chi-chan’s otherwise impenetrable expression confirms it.

Back at the cottage, they spend two hours making muâ-inn-thng together, hand-kneading jute leaves and rinsing away the bitter sap before stewing the pulp with yam, anchovy, and rice water. Before they eat, Chi-chan finally explains why she consistently refuses to dine alone with Aoyama: As a subordinate Islander, she will not share a table with a superior Mainlander, only with an equal. Aoyama asks whether they can eat together as two human beings, rather than as writer and interpreter. Chi-chan agrees, now that Aoyama is “Aoyama-san.” They share their first meal as equals: muâ-inn-thng over rice alongside Rokkō meatballs, kiâm-lâ-á clams, and pickled radish. Aoyama finds the bitter soup’s sweet aftertaste unexpectedly satisfying. Chi-chan then quietly clears her entire plate of meatballs at remarkable speed, revealing an appetite equal to Aoyama’s own. Delighted to have found a kindred spirit, Aoyama declares that they must embark on a culinary tour of the entire island. After a brief moment of surprise, Chi-chan nods and grins.