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 4)
In the season four finale, "Home", Angel receives an amulet from Wolfram & Hart which is important to the final battle in Sunnydale. Angel goes to Sunnydale in the penultimate "Buffy" episode "End of Days" and also appears in the series finale "Chosen". Angel gives Buffy the amulet (which is later worn by Spike in the final battle) and offers his help, but Buffy declines as she needs him to be the second front if they fail. Buffy and Angel share one final moment in a graveyard where they discuss a possible future.