What event does Ella learn that her father will be attending from her magic book? Who is supposed to be at the event, and what does Ella decide to do after reading about her father's plans?

Ella reads in her magic book that her father is going to be attending the wedding of a giant, and has hopes that there will be fairies in attendance. Ella wonders if Lucinda, the fairy who gifted her with obedience will be at the wedding, and if so, she imagines she might be able to beg Lucinda to take her gift back. Ella realizes that she can run away from the school to look for Lucinda, and if she does so she won't have to see Areida and hurt her feelings by treating her coldly.