This story is a sequel to On The Dark Side of the Moon

While Twilight was trapped in her nightmares, the Cutie Mark Crusaders followed the Mane 6 to Canterlot and sneaked into Princess Celestia's chambers. Now they've got some explaining to do...

A follow-on story from On the Dark Side of the Moon, which may be found here:

Twilight's day hasn't gone well. Her night is about to get a WHOLE lot worse. Starting with being banished to the Moon...

After a series of unfortunate events conspire to trap Twilight within her own nightmares, Twilight's friends - along with the with aid of Princess Luna - become Twilight's only hope of rescue. Time and Twilight's fears are already against them, but they must also come to terms with how Twilight got there in the first place...