It's a bright, sunny day, perfect for reorganizing the library! But during the task, Spike uncovers a yearbook from Twilight's time in the School for Gifted Unicorns, and learns of her first true friend: Marigold. Twilight decides that it's time to share her story of her first friendship, of how Marigold opened Twilight's eyes to the unimaginable, and of the tragedy that would push the filly duo far past what either could ever imagine.