In Hoseon, a powerful nation protected by the sable tiger, a tiger deity, the people believe their royals hold divine blood, destined to bring prosperity. Crown Prince Lee Hyo is born with the Sable Tiger's power, but his ominous, cold aura forces the palace to keep his existence hidden. Meanwhile, Seo Doram, a fallen noble turned servant after his family’s disgrace, receives a shocking royal decree: he is to become the Crown Princess. While Doram has no idea what is going on or why he has been chosen to be the crown princess as a man, Lee Hoo somehow seems to have fond memories with Doram from his childhood. What has the Sable tiger hold in the future for the two of them?