Before going to Ponyville, Twilight Sparkle connects more dots than usual, which gives her more reason to face Nightmare Moon alone. (Pamphile (PAM-feh-lee) means "friend of all" in Greek.)
A human discovers a strange book in a library, where an animated, purple pony appears on every page with the purpose of teaching friendship and solving friendship problems.
When Discord gets turned into stone the second time around, the Tree of Harmony, now older and far more developed, takes the opportunity to reform him.