Nightmares of Hogwarts (and Helena Ravenclaw)

Helena Ravenclaw is asked by her mother to reconsider marrying the man of her dreams and instead remain at Hogwarts and help protect it. However, Helena is set Waldo is the one, but when he breaks up with her, she questions how much he really loved her. Will she understand why her mother wanted her to stay? Will it be too late? And what's a Nightmare of Hogwarts? It's sorting time.