Complex sentence: Norah reveals that she led Aurora into a trap; her mother and Aurora's stepmother is in fact Umbra, the Queen of the Night, and Norah and Cordelia are Nox and Crepusculum, the daughters Umbra sent to steal Lemuria's sun and moon.
Split into simpler sentences: Norah reveals that she led Aurora into a trap and that her mother and Aurora's stepmother is in fact Umbra, the Queen of the Night. This means Norah and Cordelia are Nox and Crepusculum, the daughters Umbra sent to steal Lemuria's sun and moon.