A girl is called for her sorting. She is cunning and power hungry, but loyal. Very distinct traits.
When the Sorting Hat is placed, it takes almost ten minutes for a decision. Finally, the Hat said to the girl, "I give up. You're split between two very different houses it seems, so... which one? Hufflepuff or Slytherin?"
The girl doesn't have to think, she already knows. "Hufflepuff."
The Hat is surprised, "Really? But you won't be recognized for your cunning attributes. No one will know who you really are. They will only expect you to be loyal to a fault."
A light smile touched the girl's lips, "Oh Hat, I know this already. Hufflepuff is my choice."
"Alright then. HUFFLEPUFF!", the Hat shouted.
So the Hufflepuff's clapped, the Ravenclaw's ignored, the Slytherin's sneered at their apparent inferior, and the Gryffindor's, of course, looked with sympathy.
But there was a reason the girl chose the misfit house, the one where the loyal, honest, and kind seemed to go to.
It wasn't because Slytherin was feared or deemed "evil". Nor was it that her family would be disappointed if she were ever associated with that house.
It was because she was truly loyal... to herself.
The people she knew as family, the people she called friends, and the people that would be her new housemates couldn't give her what she really wanted... power.
Ironically enough, that's exactly what Hufflepuff would give her.
It would be too obvious what her intentions were if she were sorted into Slytherin.
No one would ever suspect such an ambitious and sly nature from a sweet and shy little Hufflepuff.
Hufflepuff will be her disguise to climb to the top of the ladder.
That is how she will achieve her ends.