In a world where lycans are feared and shunned, Ashina, a young werewolf, is being forced to marry a pack of lycans to ensure her pack's survival. But Ashina cannot bring herself to accept the idea of marrying her pack's mortal enemies. Desperate for a way out, she turns to her younger sister Yimi, who reluctantly agrees to deliver a letter to a mysterious werewolf named Lucien. As Yimi sets out on a dangerous mission to deliver the letter, Ashina must navigate the treacherous waters of pack politics and the looming threat of the lycans. Will Ashina find a way to escape the marriage, or will Yimi's mission lead to disaster for both sisters?