Roheryl has played the role of a "villainess" for over 10 years, driven by a desire to take revenge on Duke Cassian's family, who caused her mother's death. Just when she's about to execute her escape plan, she is diagnosed with a terminal illness — with only one year left to live. To save herself, she learns about a rare flower located within the imperial palace and proposes a contractual marriage with the Crown Prince, Yulion, to gain access to the flower. After curing herself, she begins creating medicine and healing others in the palace using her knowledge. Her presence gradually earns her the title of “The Light of the Empire,” and the Crown Prince begins to question his feelings as she continues to shine.