I worked my whole life to stop this from happening. Yet here I am, hidden in the shadows, rain mingling with the tears running down my face. And I'm helpless to stop it.
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.
"Her thorns dragged holes deeper into her soul. She was irreparable. They would never know of her pain. They would never understand her depression. Her life was a void of solitude and imperfections. She was alone, except for her thorns."
Rainbow Dash has to help all of her friends, and gain the courage she never had. She has to band together with some pretty unexpected ponies to save her friends and avenge Rarity.