Without giving away too much plot, season two is not quite as believable as season one, but this is a minor quibble. These episodes will keep reeling you in until the very last. This is great writing, and the proof of this is the way you begin to care about these characters, even our grim yet endearing protagonist, Dexter. Jeff Lindsay invented a character that is destined to be a classic in pop literature. Dexter is a new kind of antihero, and if you're skeptical just read the first book, DARKLY DREAMING DEXTER (the audio book is great, too). You'll shake your head in amazement that Mr. Lindsay came up with this guy!
There is some great character development in season two, especially with Dexter's sister Deborah. Every time I see an episode, I just want to give her a big hug and tell her everything is going to be all right (even though I know it's not). Jennifer Carpenter plays this character perfectly. She's a beautiful mixture of independence and need, and her romance with Detective Lundy (Ketih Carradine) is pure sparkling chemistry. Sgt. Doakes continues to hound Dexter to the point of obsession, and Laguerta ups the ante in her games of manipulation. Doakes's story arc is a heartbreaker. There are a couple of plot holes involving Dexter's Dad, but nothing I couldn't overlook. If you have a strong stomach and a love for a great story, don't hestitate to read and watch Dexter.
Read my review for season one of Dexter to get my opinion on the gratuitous nudity and language (i.e. there's a lot of it).