A South Korean agent hunts a drug ring in Russia and goes head-to-head with a North Korean operative — pulling both into peril and tangled secrets.

Upon arriving in Seoul for college entrance exam prep classes, Seoyun decides to visit her older sister, who had long severed contact with her family. At her sister’s apartment, Seoyun is greeted by her sister’s lover.

As a sole witness of the theft, Yubin secretly finds it amusing when Yerim, the most popular girl, loses her laptop. Yubin approaches Gayoung, the culprit, and volunteers to help her out.

Suyeon comes back to her hometown to find the sound that disappeared. She meets Kyungmin, whom she has not seen in a long time, and they realize that their memories are different when they share their stories.

Su-hyun, a courier who stopped acting, had a contact accident with Ji-young, an acting student, while delivering at a university. Ji-young, who had rejected Su-hyun's offer to take her to the hospital, asks for another request. In that way, the two go to Ji-young's audition in Su-hyun's truck.