While Ha-won tries to put his personality into a new AI device, he gets drawn to music coming out from the studio and meets Seo-woo by chance. Meanwhile, new studio janitor Soon-ho asks Seo-woo to buy dishes from Ji-soo.

Seo-woo gets curious about the relationship between Ha-won and Ji-soo but doesn't realize the man she met at the studio is Ha-won. Meanwhile, Ha-won and Ji-soo talks through the phone after 7 years. She decides to go to Oslo where she has met Ha-won.

After Ji-soo's accident, Ha-won falls in despair and makes an AI device with her voice. Meanwhile, Seo-woo borrows the device and tells mixed feelings about Ha-won and the device answers her that it is unrequited love.

Ha-won becomes closer to Seo-woo as they search for traces of Ji-soo together. While they talk to the AI device with Ji-soo's voice, Ha-won finds out that Seo-woo has feelings for him.

Seo-woo asks Ha-won to forget about her feelings. Ha-won succeeds in communicating with the device and tries to talk about the things he couldn't tell when Ji-soo was alive. Watching Ha-won suffer with longing, Seo-woo tells him to end his love.

Ha-won asks Seo-woo not to quit unrequited love and goes to the cafe where he planned to meet Ji-soo when she was alive. Then he decides to stop his feelings toward Ji-soo, bursting with his last emotions.