Moon in the Cage

Cold Xinyue, the eldest daughter of the Prime Minister, sees her father imprisoned by corrupt officials and exiled to the frontier, forcing her and her younger sister to flee into the common folk. Later adopted and trained as a secret guard by Prince Fu Mingyu, she is secretly embedded in Fu Minglou's mansion as an undercover agent. When she falls for Fu Minglou and they share a forbidden moment, Fu Mingyu discovers the truth and threatens to sacrifice one of them by holding her sister hostage. Forced to choose between her sister and Fu Minglou, Cold Xinyue betrays her lover. Years later, when Fu Minglou returns with his achievements, what sparks will their reunion ignite?