Angel: I Will Remember You

Buffy comes to confront Angel about his lack of contact with her during a secret visit to Sunnydale. They are soon tussling with a violent demon before she can head out of Angel's life for good, but the demon's death allows Angel to find out he is human, and he plans on making up for lost time with Buffy. When the demon returns, stronger than ever, Angel's rekindled romance with Buffy is doomed, as he realizes he can only protect her by having himself turned into a vampire once more.