Twilight Sparkle gets teleported to a mysterious dungeon that she quickly figures out is based on puzzles. She needs to beat ever single puzzle to get to the next door to solve the next puzzle. Each puzzle is rated on the number of the door and there are ten puzzles, so obviously number ten is the hardest.

So all she has to do is complete every puzzle to go home.
( Spoilers! )
[size=10]( duh )[/size]