Ha Won runs a company called AH and is an AI programmer. His latest project is a conversation device with his own personality programmed into it. Ha Won wanders into a recording studio where he meets sound engineer Seo Woo. After their meeting, Ha Won’s device finally starts working. Meanwhile, Seo Woo gets a weird request from her new boss.

Seo Woo blames herself for meddling in Ha Won and Ji Soo’s complicated relationship and causing Ji Soo pain, but she can’t help but grow more curious about Ha Won. She ends up telling the man she calls Before Dawn about this situation. Meanwhile, Ha Won and Ji Soo speak to each other on the phone for the first time in seven years and plan to meet up.

Seo Woo has a tough time after Ji Soo’s accident in Norway. However, she finds herself worrying about Ha Won more than herself and is caught off guard by these emotions. Ha Won wants to know more about Ji Soo through Seo Woo. As they continue to meet, Seo Woo discovers another one of Ha Won’s secrets.

Ha Won still wants to know what the point of reaction was for Ji Soo’s conversation device. As Seo Woo continues to help bridge the gap between Ha Won and Ji Soo’s character within the device, the two become closer to each other. Meanwhile, In Wook goes through a slump after Ji Soo’s death and keeps bumping into Soon Ho.

Seo Woo’s feelings for Ha Won are now out in the open. Seo Woo is quite embarrassed by this, but she continues to help Ha Won get closer to Ji Soo. Finally, Ji Soo agrees to have a conversation with Ha Won. However, Seo Woo figures out that Ji Soo will eventually remember what made her miserable and wants Ha Won to stop.