Warrior Princess Katherine Stirling is betrayed by her fiancé, who vanishes with the Military Tally. Katherine forcibly marries his older brother Morgan Lane as her Imperial Consort. Morgan Lane, her secret protector, loves her. After marriage, they suspect and test each other. Crises from Elder Princess Charlotte Stirling and Imperial Spy Holt Voss. Katherine and Morgan Lane unite, fend off Empress Churchill and Elder Princess's faction, expose Holt Voss, retrieve the Military Tally.