While Chrysalis, Tirek and Cozy Glow try to figure out how to activate the bell, Grogar sets out to the Castle of the Two Sisters to confront the spirit of the Tree of Harmony.
Under the light of the moon, King Thorax and Prince Pharynx come face to face with the changeling's grim past - a dark crown, and the beast that still wears it.
Sequel to "Daughter of Discord." After living with the Discord family, Mothball thinks he is ready to take the next step with Screwball. Their plans are put on hold when the changelings want Mothball for their king.
Discord, the Lord of Chaos and final key-giver, gets a visit from a shadow that claims to be Tirek and threatens to destroy the mane six out of revenge.
Side story to "The Not-So-Normal Adventures of King Sombra and Pinkie Pie". Pinkie reflects on her relationship with Sombra after she finds out he's been injured from Tirek's attack on the Golden Oaks Library.