Originally Posted by
MD
Just be careful with that, a lot of people watch the series and end up disappointed.
Basically, without spoiling anything, it's an adaptation of the manga, which is separated into arcs; one of the first arcs is a flashback arc which explains how the main characters met, and the anime is an adaptation of that arc (other than the first episode); it ends when that arc ends, which happens to be an incredibly frustrating end-point.
Still one of the best anime of all time, though; the movies are spectacular too.
Speaking of "one of the best anime of all time":
One of the best works of fiction surrounding time-travel I've ever seen. Some f-cked up shit.