Angel (season 1)
At the end of the third season of "Buffy", the 242-year-old, re-ensouled vampire Angel left Sunnydale to give teenage Slayer Buffy Summers the chance to live a normal life. Angel is now living in the big city of Los Angeles. With Buffy gone Angel is now completely cut off from society, every day getting closer and closer to giving in to his vampiric hunger. It's not until he befriends the half demon and fellow Irishman Doyle, who is sent visions of people in trouble by The Powers That Be, and fellow Sunnydale resident Cordelia Chase, who grounds Angel's life in the humanity around him, that he truly begins to take charge of his life and seek atonement for his past sins. He sets up his own detective agency, Angel Investigations and begins to "help the helpless".
Angel (season 1)
In the two-parter, "Five by Five" and "Sanctuary", the rogue Slayer, Faith shows up in L.A. and is contracted by Wolfram & Hart to kill Angel. After torturing Wesley she ends up breaking down in Angel's arms, screaming at him to kill her. She eventually admits to the many crimes she has committed and hands herself in to the police. Seeing someone else so willingly seek redemption allows Angel to re-affirm his role and to willingly cut himself off from Buffy. Angel also develops a friendship with Faith, sharing a powerful bond which would eventually be pivotal in their future alliances.