Love Countdown! 

Yoo Min-hee, who just witnessed her boyfriend cheating on her, returns home crying and runs into her childhood friend Park Hee-min. After seeing Minhee crying, Heemin proposes to Min-hee that the two of them make a love contract…?! These two people were once best friends, but as time passed, they drifted away from each other. What will happen to this love countdown that started?