Overview:

Seonghwan is invited to Hyejung's house. On the day of the invitation, I see Hye-jung's sister, Hee-soo, and fall in love with her at first sight. Hee-soo also continues to be attracted to the old first love and younger Sung-hwan. Seong-hwan and Hee-soo have a conflict between their sister and brother. Eventually, my sister secretly engaged in love affair, Sunghwan, who can't miss both, I make an extreme choice to love.