Thank you for having both Derpy and Twilight. I've heard a lot of hate from hardcore Doctor x Derpy fans about having Twilight as a companion. He's had more than one companion at a time before. There doesn't have to be anything romantic between the Doctor and Twilight. Hell, They would be an awesome team. Twilight and the Doctor are both smart, and she can use her powers to battle Daleks.
Story: The TARDIS has lost power, via a rookie error. (And by rookie, of course, I mean Derpy.) So Luna is being awesome and pulling them... somewhere. Ok, honestly, I didn't really think past Luna being awesome, so...
Its not a smart idea to travel in the vortex without a capsule or ship...any Time agent with a vortex manipulator will tell you that...Hopefully she will get back aboard the Type 40 Tardis before they exit the Time Vortex
Someone should do a picture of the epic climax where Tenth Doctor & Princess Luna fight a Nightmare Moon possessed Twilight! [link] I think this would be a good theme for The Doctor's Last Stand![link]
Nah, she's just helping them travel the Circuits of Time so Twilight can get her history report to Celestia in time so Spike can avoid military school. Truly they are in for a most Excellent Adventure!*air guitar rift*