90 il, sarang hal sigan - Season 1 (2006)

While meeting for the first time in years, Ji-seok asks Mi-yeon to live with him for three months, causing both of them to reminisce about their past together. Noticing a sudden change in behavior, Tae-hun suggests Mi-yeon take time off from school, while Jeong-ran asks Ji-seok if there's another woman.

After coming back into each others' lives, Ji-seok and Mi-yeon find it difficult to connect with one another, causing Ji-seok to impatiently wait for Mi-yeon to call him. Meanwhile, Ji-seok pretends to be a client in order to meet with Tae-hun; Mi-yeon is devastated when Ji-seok tells her he is sick.

As their emotions for one another begin to resurface, Wal-suk tries to talk Mi-yeon out of committing adultery. After answering questions from Byeong-chan at the hospital, Ji-seok calls Mi-yeon, causing Jeong-ran to once again question if he is seeing someone else, despite the circumstances.

After seeing Mi-yeon and Ji-seok together, Jeong-ran questions if Ji-seok is pretending to have cancer, in order to leave her for Mi-seok. Tae-hun asks his boss for a transfer to San Francisco, claiming Mi-yeon wants to move there; while Jeong-ran calls Mi-yeon and asks to meet her.

Jeong-ran and Mi-yeon meet, while Ji-seok makes plans to move into Mi-yeon's old house. Jeong-ran asks Ji-seok's mother to move into their apartment, and Tae-hun tells Mi-yeon over dinner that he asked for a work transfer and they are moving to San Francisco.

Mi-yeon learns that Tae-hun and Ji-seok met, after finding Ji-seok's business card in Tae-hun's coat. While Ji-seok's mother moves into his apartment, Jeong-ran surprises Tae-hun at his office after learning about his recent meeting with Ji-seok. Mi-yeon and Ji-seok cross paths again outside of her apartment building.

After crossing paths outside of her apartment, Ji-seok gives Mi-yeon keys to his new apartment. The dean abruptly tells Ji-seok he should take a leave of absence from the university; Tae-hun and Jeong-ran begin to feel the consequences of Ji-seok and Mi-yeon's rekindled relationship.

Ji-seok and Mi-yeon take an overnight trip to the coastline, leaving Tae-hun and Jeong-ran wondering if they are together. As Jeong-ran calls Tae-hun to suggest they meet, Ji-seok finds himself waking up in a hospital room with Byeong-chan after losing consciousness while waiting for a tow truck with Mi-yeon.

Granting his daughter's Christmas wish, Ji-seok takes Hye-jin on a date to a musical and expensive restaurant, where they cross paths with Tae-hun. After suffering from severe pain in the restaurant, Jeong-ran decides to take Ji-seok to Jeju Island; Mi-yeon decides to visit her home in Jeju as well, after her relationship with Tae-hun continues to fall apart.

Mi-yeon tries to explain to Tae-hun how much Ji-seok means to her, but Tae-hun does not understand and returns to Seoul alone, where he is asked to submit his resignation. As Byeong-chan reveals to Ji-Seok's mother that he will die soon, Ji-Seok reminisces on his life and struggles with his fate.

After collapsing at the airport, Ji-seok is taken to the hospital; Tae-hun convinces Jeong-ran to let Mi-yeon see Ji-seok, but tells Mi-yeon she must return to him after Ji-seok dies. Ji-seok decides to live in a hospice until his death, choosing to not see Mi-yeon anymore.

Although Ji-seok refuses to take Mi-yeon's phone calls, Mi-yeon visits him after being asked by his mother to do so. Tae-hun finds it difficult to focus on his work, while Mi-yeon, Ji-seok, Deok-gu, and Byeong-chan spend time together like they used to do when they were kids.

Jeong-ran and Tae-hun surprise Mi-yeon and Ji-seok by showing up at the hospice, and taking Ji-seok home; Jeong-ran is hurt when she finds out Ji-seok's mother asked Mi-yeon to visit. After being admitted to the hospital and regaining consciousness, Ji-seok confesses his love for Mi-yeon and asks for one last wish.