Beginning with a nice piece of misdirection that suggests the story will focus on the three armour-plated vampire warriors, Angel soon spins off into far more unexpected territory.
At the beginning of the season, Angel seemed simply to be some sort of shadowy plot device who would turn up to drop hints to Buffy when the team had exhausted whatever leads they'd been pursuing. From this episode on, the redefined relationship between Angel and Buffy forms the backbone of the series.
The revelations about Angel's past are only a taste of what's to come, and it quickly becomes apparent that his relationship with the Slayer is going to be a troubled one. There's obvious chemistry between all the actors, not least between Gellar and Boreanaz, who start to smoulder in this episode.
The story is cleverly constructed, with several plot threads developing in parallel. At times the switching between the different settings becomes tiresome, and the pace seems to be maintained at the expense of frustrating the viewer. Two scenes are especially well handled: Darla stalking Joyce Summers, ("Would you like something to eat?"), and the kinetic, John Woo-style battle at the end of the episode.
It's a shame to see Darla written out, especially as she was responsible for making Angel a vampire. Angel is a pivotal episode, rich in character-building detail, and one that serves the long-term interests of the series. It is, nevertheless, rather mundane.