Based on Mario and Luigi: Partners in time. One of the scientists has just discovered a way to travel between the timelines throughout Equestria. Princess Celestia along with two other ponies have been selected to go on a test run. However, the past doesn't seem to be right. It is now being invaded by an alien race known as the Shroobs and Princess Celestia has been captured. Can Applejack, Rainbow Dash, and Rarity fix the past and save the princess?

Inspired by DryvernX's story Twilight and Rarity Partners in Time.