Whats this show called?!

Whats this show called?

okay i was watching tv one day and there was a show on and i dont knoe what it was called. but i remember there was a son and father that lived with the kids stepmom and stepsister. i know the sons name was sebastian and his stepsisters name was catherine. nd sebastian fell in love with a girl at his skewl but she was really just messing with him. nd she had a friend named sarah. she was really ditzy nd rich. thats all i got. can anyone help me? sorry i dont have much

1 week ago
it was on FX

1 week ago
okay i got it. its cruel intentions 2. and it was a movie. it just seemed like it was a show cause it was only like an hour. prolly cause they cut everything out. lol

http://www.imdb.com/title/tt0139134/... it's cruel intentions has Buffy in it