After being scammed while trying to buy her family home, In Yoon-joo seeks help from her twin, Kang Sun-jun, a doctor who treats somnambulism, only to be mistaken for her by CEO Moon when Sun-jun suddenly leaves the country. Caught in the rain, Yoon-joo finds comfort in a bookstore that evokes her late father, an uncanny feeling shared by LUNA's member Seo Woo-yeon.
