You needn't have amped up for the season-three premiere of Dexter by taking the show’s "killer instinct" online quiz (on which we scored 40 percent). You'll want to tune in to watch everybody’s favorite serial killer–forensics expert, Dexter Morgan (played to darkly sunny perfection by Michael C. Hall), who thinks he’s settling into normal life when he accidentally kills an apparently innocent man. New cast addition Jimmy Smits adds his lumbering Latino gravitas as assistant district attorney.