During what started as a perfectly fine Lunch, Twilight learns that her friends have somehow gotten it into their heads that she is in a relationship with her mentor and idol Princess Celestia.
One night a year, on the Eve of the Summer Sun Celebration, Princess Celestia is sad, at least according to Twilight's observations. She has a plan, a boardgame, and is determined to try to cheer up her mentor.
Twilight Sparkle has been living a lie. Everypony told her what a beautiful and accomplished mare she was. Everypony thought she was a responsible adult. They were wrong. She was still just a filly trying to stumble her way through life.