A young man named Kanji Nagao moves from his rural hometown in Ehime Prefecture to Tokyo for a new job at an advertising agency. He is shy and earnest, struggling to adjust to the fast-paced city. At the airport, he is greeted by a colleague, Rika Akana, a vibrant and free-spirited woman who has lived abroad and approaches life and love with an almost unsettling directness. She immediately gives him the nickname Kanchi.

Kanji soon reconnects with two childhood friends also living in Tokyo: his best friend Kenichi Mikami, a charming and uncommitted medical student, and Satomi Sekiguchi, a gentle and traditional woman whom Kanji has secretly loved since high school. However, Kanji quickly realizes that Satomi’s affections are directed toward the more sophisticated and unpredictable Mikami. This creates an immediate emotional distance between Kanji and his dream girl.

As the four friends navigate their new lives in the bustling metropolis, romantic tensions rapidly escalate. Despite the office rumor that Rika is having an affair with their married boss, she boldly confesses her love to the bewildered Kanji. While Kanji remains fixated on the unavailable Satomi, he finds himself gradually drawn to Rika’s relentless optimism and unwavering devotion. She represents a chaotic, passionate modern world, in stark contrast to the traditional, safe love he thought he wanted. For a time, Kanji and Rika become a couple, their relationship marked by passionate highs but undermined by Kanji’s lingering doubts and inability to fully commit to her intensity.

Meanwhile, the relationship between Mikami and Satomi proves unstable. Mikami’s flirtatious nature and inability to be faithful drive Satomi into a state of constant anxiety and heartbreak. She frequently turns to the dependable Kanji for comfort, creating a wedge between him and Rika. Mikami, in turn, becomes involved with a wealthy classmate named Naoko Nagasaki, who is engaged to another man. This final betrayal leads Satomi to break off her relationship with Mikami for good. Lonely and hurt, she begins to see Kanji not just as a friend, but as a potential life partner, reigniting his old feelings.

The central conflict reaches a breaking point when Rika is offered a transfer to the company’s Los Angeles branch. She sees this as a final test of their love and asks Kanji to stop her from going. Unable to choose between the safe familiarity of Satomi and the overwhelming love of Rika, Kanji hesitates and falters. In a desperate attempt to salvage the relationship, Rika travels alone to Kanji’s hometown in Ehime, the place where he is most himself. Kanji follows her there. On the platform of the local station, Rika gives him a final chance, asking him to meet her at the station by a specific train time if he wants her to stay. Kanji arrives late, only to find she has taken an earlier train, leaving behind only a handkerchief and the memory of her smile.

The series concludes three years later. Kanji has married Satomi, settling into a conventional and predictable life. Walking through Tokyo one day, he spots Rika on the street. She is as vibrant as ever, smiling her brilliant smile. They exchange a few polite words, then turn and walk away from each other, heading in opposite directions down the busy sidewalk. Though he now has the stability he once craved, Kanji is left with the lingering ghost of a love he was too afraid to fully embrace, while Rika disappears into the crowd, free and unforgettable. A modern remake of the series was produced in 2020, updating the setting to the present day.