Lira, a young noblewoman of the once‑prestigious Tachibana family, has been treated with cruelty by her relatives — confined, mistreated, and forbidden to walk in the sunlight. Her only hope of escape lies in a marriage proposal she makes, using leverage over the withdrawn eldest son of the distinguished Nishioka duke family, Azumi.

Though their union starts as a desperate gamble, neither realizes just how complicated — or intense — their relationship will become. A tale of pride, devotion, and unexpected love begins as two solitary hearts confront destiny, social stigma, and the shadows that linger in twilight.