1. A wicked troll created an evil mirror that made everything good and beautiful appear ugly, distorted, and wrong. When the mirror shattered, small pieces flew everywhere and got stuck in people's eyes and hearts, causing them to see the world negatively.
2. The story introduces Gerda and Kay, two children who live next door to each other and spend their days playing in the small garden between their windows.
3. One day, a small shard of the evil mirror gets stuck in Kay's eye and heart, changing his behavior and causing him to say mean things and tease Gerda.