When a strange foe kidnaps all of Twilight's friends, it is up to Twilight to participate in the greatest gladiator match in recent Equestrian history: The Princess of Friendship vs the Lord of Enmity!
Enraged that she had been exposed, Starlight retreated into the tunnels. However, she forgot two, very important things that she hadn't even thought about before running off.
A brown leather journal signed by one "Dream Snatcher". Upon making contact with subject's skin, the object causes visiual, auditory and tactile hallucinations of an exceedingly violent matter.
Twilight went alone to the Crystal Empire at the request of Princess Celestia, but unfortunately, she failed to save the city from King Sombra, and now she is trapped by King Sombra's trap and needs to find a way out.
Despite her best efforts to maintain harmony, Celestia can't get the mortal ponies of Equestria to stop hating on each other for more than a millennium. So she's just burn everything.