Disclaimer, this is my first non spider-man story.

Luna has not been seen for three days, so Celestia, after the usual meeting, goes to investigate, Will she find the Princess of the moon? Will she find Equestria's resident human? Will she finally get the cake?!

Teen tag is for partway through.

Image Source: http://sircinnamon.deviantart.com/art/Celestia-is-shocked-SHOCKED-271834680