Scootaloo is living a good life right now. She is able to fly quite well now thanks to Rainbow Dash's assistance and is getting better and better at it. She has her own special somepony, Rumble, and while they aren't the most romantic couple in the world, he is somebody Scootaloo knows she can fly with at any time. All and all she is living a pretty good life.
And Diamond Tiara does not like that. As she watches Scootaloo from afar she is jealous over all Scootaloo has managed to accomplish and all the friends she has. So as soon as Silver Spoon comes back with new look that makes colts drool, Diamond Tiara hatches a plan. To steal Rumble away from Scootaloo.