Bosomy Younger Sister.

Bo-ram and Hyeon-woo are friends in the neighborhood that I knew since I was young. The two, who were just like children, became adults and began to love each other. Bo-ram prefers a lighter love rather than a more serious one, and Hyun-woo likes only one woman... Hyeon-woo gets help from Bo-ram in many ways to win his favorite Seo-yeon. And as a friend, Bo-ram starts a special class for Hyeon-woo... In the midst of this, Hyeon-woo realizes that his true love is not Seo-yeon but Bo-ram, and he struggles to choose between friendship and love. This is how people in their 20s start their own unpredictable love story.