It is Buffy's 19th birthday. After realizing he is a grown man hanging out with a bunch of teenagers, he begins to feel useless. He is also the last person to learn about Riley and the Initiative. To top things off, he has a confrontation with Ethan Rayne that ends in drinks, but he transforms into a demon the next day and seeks help from an unlikely source.
This episode was OK. I like seeing birthday episodes for Buffy every season since season 2. They're usually pretty cool. This has probably been my least favorite one so far, though. I like Riley though. He's sexy. The plot for this episode was OK, but I'm not liking a lot of the fourth season. It has its moments, though. :)