The pilot episode of Dexter promised a plethora of possibilities in regards to character development and subplots. "Crocodile," the second installment in the Showtime series, not only fulfills those promises, but twists the show in unexpected directions.
If Dexter is about anything, it's about duality, and "Crocodile" homes in on that premise from a number of angles. Firstly, there's Dexter himself — forensics expert by day, serial killer by night. But, as explained in the pilot, he sates his bloodlust by killing only really bad people. In "Crocodile," a more fully realized character is emerging. Despite Dexter's claims (largely via voiceovers) that he is incapable of feeling, his actions prove otherwise. He claims that while others would see the anguish of a hit-and-run victim's family as tragic, he views it as an opportunity. When the drunk driver is acquitted, it's apparent who Dexter's next prey is.
Dexter's somewhat unique method of meting out justice has to take a backseat to more pressing matters, though. The Ice Truck Killer continues to taunt Dexter with clues about his own killing spree, playing a twisted cat and mouse game by leaving doll parts in Dexter's freezer, signifying the killer knows what Dexter does in his spare time. This is one of the threads that sets Dexter apart from other detective series, but by no means the only one.
Duality comes into play again when we find that Sgt. Doakes has a motive beyond retribution in his single-minded pursuit of tracking down the killer of a slain undercover cop. And then there's Lt. LaGuerta — besides her advances to Dexter, why is she so doggedly determined to undermine Deb's investigation of the Ice Truck Killer?
"Crocodile" introduces a new potential subplot in its rendering of Cuererro, a Cuban druglord who all the principals know ordered the hit on the undercover cop, but can't — or won't — pursue. The stage is set for more subplots involving police corruption, but that's only speculation on my part.