An enigmatic clan called the You Tribe has long inhabited the remote Moonlit Archipelago. Beneath the islands lie massive uranium deposits, drawing the greed of competing factions. Amid internal strife among the clan’s island lords, the old You King is assassinated. With his dying breath, he entrusts his secretly trained disciple—Li Yebai, the mighty Emperor of the world-renowned assassin group “Phantom Empire”—to unravel the conspiracy and avenge him. He also places his daughter, the newly crowned You Queen Yu Luochang, under Li Yebai's protection.