Mad that Angel was in town and stayed hidden, Buffy comes to LA.  When fighting a demon, Angel gets some of its blood on him and becomes fully human.  Angel and Buffy spend the day making plans for their future (and other things).  Later, Angel tries to take on the regenerated demon by himself but has to be rescued by Buffy.  Deciding that his and Buffy's love would destract them both from the fight against evil, Angel gets the Oracles to return him to human.  They reverse time so that he is never infected and no one but him remembers what went on.