Ella, a serf maid, ventures into the forbidden chamber of Frostspire Palace to find her missing mother, where she encounters Cassian, the "mad prince" imprisoned by silver chains for nine years. She soon discovers that Cassian's madness is not a curse, but the result of eighteen years of poisoning with aconite by the ruling Empress Octavia. Under Cassian's pillow, Ella finds the moonstone hair comb she lost three years prior. When the two combs are reunited, her Moon Keeper lineage awakens, and a Mate bond forms between her and Cassian. Her blood can bring temporary clarity to the out-of-control Cassian, but it also transfers the wolfsbane poison into her own body. After her identity is exposed, Ella is exiled to the White Wasteland, used as bait by the Empress to lure out Cassian and the hidden wolf clan. Cassian breaks free from the silver chains and chases into the blizzard, shifting fully into a black wolf for the first time. At the Sanctuary of Moonfall, the two uncover the truth behind their parents' murder and the usurpation of the throne, and learn that the Empress plans to steal their powers on the night of the Blood Moon. The pair, who had originally planned to flee by ship, decide to return to the royal palace. During the Blood Moon ritual, Ella feigns death using "Moon Slumber", and before the third bell tolls, gives her willing blood to Cassian, prompting the Moon Crown to recognize the rightful heir. Octavia, who forcibly tried to steal their blood, suffers a ba
