To protect herself from her abusive adoptive family, an orphan mastered the act of being a gleeful and submissive daughter. When she dies in an accident, she believes that she is finally free. However, fate cannot be more cruel; she is reincarnated as Rudbeckia "Ruby" de Borgia, a minor villainess from a novel who grows up in a violent household and dies at the hands of her husband.

Ruby's father, the power-hungry pope, wishes to ruin the Britanya Kingdom by marrying Ruby off to Britanya's mightiest knight, Iske van Omerta, and having her poison his beloved sister, Elenia. But Ruby knows his plan will ultimately fail, and no member of the Borgias family will escape Iske's wrath and revenge alive. In order to prove her innocence when the time comes, Ruby must act as an oblivious and docile wife, for only by winning her husband over can she hope to survive.