After trying desperately to escape from the meteor shower; Gwen, Heather, Courtney, Bridgette, Lindsay, and Izzy awake to find themselves in a strange world inhabited by mutated, talking horses. Understandably, the girls are pretty freaked out, and Princess Celestia is asked to help calm the situation.

Long story short, each girl is placed in the home of one of the Mane 6, who will be their "guide" to adjusting to Equestrian life. Slowly but surely, the girls begin to adapt to their new environment. However, just as they begin to fit right in, new evils begin to emerge, and will be rooted in the issue of how they came to Equestria in the first place. [Total Drama Series Crossover]

Image has nothing to do with the plot of the story, I just thought it looked cool.