"I don't understand LOVE. How can you feel special around someone and not feel the same around others?" "Isn't that what makes love so interesting and unique?" "No, it makes love annoying and confusing." 23-year-old Yang Munhee doubts the existence of love, and 25-year-old Kim Taehyung believes love is the key to all the locked doors in the universe. He was once Munhee's older brother Jeongin and sister Hana's best friend. What would happen if they reunited in a way both could never imagine? Read to know what happens . . .