Even for ponies such as Twilight Sparkle, magic is something that's both easily understood, yet full of unknowns at the same time. Wondering about the mysteries surrounding magic and its relationship with Equestria as a whole after an innocent question, Twilight tries to research whatever she can about the subject.
However, there is something ominous brewing in a distant land that may relate to Twilight's questions about magic, but solving some of those mysteries will require more than just research. She'll have to overcome her most dangerous challenge yet in order to uncover the truth.