Its "Buffy the Vampire Slayer" by maryperk
Summary:
Faith Lehane was called instead of Buffy Summers. When Faith dies for a few seconds at the hands of the Master, Buffy the unknown potential still living in Los Angeles is called unbeknownst to the Council. This fact is discovered when Faith sacrifices herself in her sister's place four years later. Buffy and her own group of Scoobies come to Sunnydale. Will Faith's friends and family accept this new Slayer? Written for the Third Slayer FFA challenge, round 9.
You can find it on her website Wicked Temptations,
http://www.sinful-dreams.com/wicked/temptation/index.phpEnjoy
