It's about four girls (Spencer, Hanna, Aria and Emily) who lost a friend named Alison a year previous to the first episode. Alison is more of a nasty piece of work; that friend you hate having around. The first episode begins when Alison's body is recovered and the four girls attend her funeral. At the end of it, they each get text messages from someone named "A".
Basically, to sum it up, "A" is a creepy stalker that plays lots of mind-games and tries to sabotage the four girls as much as possible. He/She threatens to out their deep dark secrets-which seem to be pretty bad for anyone.
Any-who, the season finale was this week. There was a masquerade ball before "A" was un-masked. But it was really an accomplice- Maybe. It's an addictive show and the last episode had a homage to Psycho, which was pretty awesome.
|tell me someone else noticed this. This chick had to be important...|
The season ends with Spencer linking "A" by clothes and gum and having to fight off "A" (one of the "A"s)
This site has a more thorough (and less confusing) write up of the episode with lots of screen caps from the show.
All images from We Heart It