Long ago, Twilight and her friends were in a top secret research space station. However, their field trip went horribly wrong. It was soon attacked by unknown aliens, forcing them to retreat to earth, But when they got there, Twilight was gone.
Some time has passed, and now the space station and even Twilight have been forgotten. Only the problem is, the aliens are still there. Now everpony is going back to space to deal with them, but after what they find, this may very well be the first war between aliens and Equestrians.

Picture is not mine, and I shall not take credit for it.
Attention: Chapter 6 is done, but it may be some time before I finish editing it.