The Original First love (Klaus/Elijah love story)

What if when Katerina petrova was in London meeting Klaus she had a sister a twin to be exact and she could rival her beauty to anyone she met and now she's a vampire looking for revenge on her sister and she just found out the way to do it and it involves the doppelganger and the famous Original Klaus read on to find out what happened that was so bad and why she wants that revenge and will she find love in that small town of Mystic Falls who knows?