Kim Doyun dreamed of a happy cohabitation with his childhood friend and long-time crush, Seo Ihwan. However, due to Doyun's mistake, the soul of the popular idol Ion is now lodged in Ihwan's body! The swapped soul explains that he can only return to his own body by satisfying his desires and replenishing his Yang-qi (life energy)... Caught between Doyun's desperation and Ion's dangerous games, a perilous love triangle begins to form in the most intimate of spaces.