Between Crown And Heart - Book 2

Before Galaxy Charmé arrives back at Hogwarts to attend her fifth year, already bad things had happened.
Dementors showed up in her street and tried to kill her and her sister.
She tries to defend themselves and uses spells in front of a muggle, her sister, which gets Galaxy into trouble with the ministry.
In addition, Harry starts behaving strange. He's more angry and annoyed by his friends.
Her crush on Snape is already known by everyone and still yet she can't confess her feelings. Instead she does a very stupid mistake which causes distance between her and Snape.
Additionally, a new professor turns Hogwarts into hell and teaches her that her feelings towards a much older man is inappropriate and is not tolerated by her.
This and the unrolling of her true task, which is not rescuing the world as told by everyone, causes her to join Dumbledore's Army.
Most importantly, she discovers what an evil and disgusting system the Ladyhood is and how close this makes her to Voldemort.