Due to her weak constitution, the youngest daughter of the Rotary family does not come out of the house. A vulnerable lady, Crystal Rotary. In fact, she is a man. A family where only girls are kept alive and boys either become corpses or heirs. With no influence nor strength, Crystal's only goal is to leave the Rotary family and live a normal life. Growing up like a daughter to survive and holding his breath like a dead man. After finally escaping, he's getting married? Backed into a corner, Crystal proposes to Grand Duke Pentrine, who is politically at odds with the Rotary clan. Thinking that his proposal was going to be rejected, a letter of marriage approval returns, and Crystal escapes to Pentrine's estate. The cold master of the North, a cruel person with an ice-cold heart. Crystal meets Ilian Pentrine and got married. How did that happen? (Source: Kakao Entertainement Corp., translated)