Basically, I think that the next to the throne whould be the little princess, but freya don’t think the daughter of an ex-dancer can be queen, so she's plotting to make izak the next king, and make him her husband, so SHE can be queen, because she feel that she is MORE worthy of that title.
This except I wanted to add that she has a huge xenophobic streak hence feels she has more right to be queen than the princess herself. She is an ambitious girl but her "values" are corrupt and twisted to the point she's plotting against the current heir and willing to use Izek and even bff Ellen to achieve her goals.
sorry what’s the treason Ruby mentioned??