Marnthian - Chrysalis' most trusted advisor - had disappeared after the failed invasion and had been thought dead by everyling. Then Chrysalis receives a letter from him asking her to meet Zecora and learn about Nightmare Night. Then another for... something called a human. Long story short, she gets to learn about all the holidays!

Thanks goes to DJSkywalker for keeping me on track and Zecora's lines in the first chapter! He's a great guy and his stories are even greater, go read some!