In 2006, the premium cable network Showtime introduced us to Dexter Morgan (Michael C. Hall), the unassuming Miami Homicide forensics expert and prolific serial killer.  The series became an instant hit, providing mainstream audiences with a truly compelling weekly drama which also included buckets of plasma and gore, appealing to those of us who enjoy that sort of thing.

The first four seasons of Dexter have all been unusually well executed, a rare feat for any television series.  This was accomplished largely because of the series’ incredible cast and its fantastic writers.  Moreover, Dexter has featured some of the most memorable “bad guys” in recent memory, all of them brought to life by character actors of extraordinary talent.  The writing staff has optimized the show’s most fundamental idea, one that’s fraught with dramatic possibilities, to its fullest potential – our protagonist is, after all, a homicidal psychopath.  And there’s been no blueprint, with each season uniquely composed of new twists and formidable antagonists, keeping us guessing, and most importantly, keeping us watching.

So how does Dexter Season 5 stack up to the body of work preceding it?

Unfortunately, the answer is not very well.  Now, to be fair, an incredibly high bar has been set.  Has Dexter jumped the shark?  No, but it’s safe to say that there are fins in the vicinity.

Season 5 begins in the wake of Rita’s murder by the Trinity Killer.  Dexter, having no empathy and unable to feel anything, reacts to his wife’s death in a predictably atypical way, confusing Rita’s kids, Astor and Cody, and raising the concerns of his sister Deb, and his coworkers at Miami Metro Homicide.  Dexter’s awkwardness raises suspicion in Deb’s partner on the force and Season 5 love interest Joey Quinn, in particular, who thinks Dexter may have been involved somehow with the Trinity killings.

In the meantime, Dexter stumbles upon what he believes is a serial killer named Boyd Fowler.  When Dexter tracks down and kills Boyd, he discovers that Lumen Pierce (Julia Stiles) – Boyd’s next intended victim, witnessed the killing, presenting Dexter with a huge problem.  However, Lumen eventually tells Dexter that the torture killings from which she’s been spared are being committed by a group of men that included Boyd and that she’s intent on getting revenge.

As expected, Dexter’s sister Deb (Jennifer Carpenter) unknowingly finds herself in the midst of Dexter’s peculiar method of meting out justice, while sorting through her own personal turmoil.  First, she’s forced to take the blowback from Homicide’s mishandling of the “Santa Muerte killings” – a series of ritualistic beheadings by a South American organized crime outfit.  Then, Quinn (Desmond Harrington) hires a sleazy suspended cop named Stan Liddy (Peter Weller) to investigate Dexter, while simultaneously courting Debra.  As Dexter and Lumen pick off members of the torture killing group, Deb puts together a remarkably accurate profile of the person/people responsible for the murders.  And of course, unbeknownst to Deb, her conceptual “revenge killers” are her brother and his new “tenant”, Lumen.  Inevitably, things come to a head in typical Dexter fashion.  Welcome to the meat of Season 5, folks.

There are several disappointing weaknesses that have shown up this year.  The show’s subplots are not as well conceived and are therefore less consistent, sometimes disappearing from the story altogether (Santa Muerta killings) and often times only existing to force characters to do things that they wouldn’t do organically in order to serve the broader plot (Dexter’s relatively ambivalent reaction to Lumen discovering his murderous secret).  Julia Stiles as Lumen is good, but she doesn’t have anywhere near the same onscreen presence as Jimmy Smits’ Miguel Prado from Season 3 or last season’s Arthur Mitchell – The Trinity Killer, played brilliantly by John Lithgow.  Lumen serves neither as a foil nor an antagonist for Dexter.  And the love interest angle is largely ignored until extremely late in the season.  This leaves a huge void.  Peter Weller is a bright spot and he obviously has the chops to provide the show a spark as Stan Liddy, but his character is only a bit part, albeit an important one.

At times Season 5 edges perilously close to self parody.  For example, episode 10, entitled “In the Beginning”, features a scene in which Dexter is gathering his killing supplies while he waits for Lumen to join him.  He has his knives laid out before him and he’s dressed in his iconic killing outfit – the army green long sleeve thermal shirt, the black gloves, the khaki pants, etc.  Lumen emerges from the other room, dressed identically and, as if Cupid sprinkles love dust from the heavens, Dexter is smitten.  Nothing says romance like a set of his and hers serial killers.  This scene is as cringe-inducing as anything I’ve seen in recent memory.

These issues are not as egregious as when Dan and Rosanne Connor won the lottery, or when the Fonze donned water skis, swimming trunks, and his leather jacket and literally jumped the shark.  But the show has unmistakably lost its mojo.  A huge contributing factor may be what has occurred behind the scenes following last season.  Executive producer and series writer, Clyde Philips stepped aside after Season 4 and is now a consulting producer.  This is no small loss as Philips had been nominated for the Writers Guild of America Award three consecutive years for his writing on Dexter.  Chip Johannessen, formerly of the series, 24, stepped in to Philips’ previous position which inevitably moved the writing team in a different direction.

Dexter is only as compelling as his antagonist is.  Pitted against the Ice Truck Killer whose cat and mouse game sucked us in as much as it bedeviled both Deb and Dexter, the series hit the ground running.  When Dexter’s dumping grounds were discovered and the murders were attributed to “The Bay Harbor Butcher”, Dexter was hunted by everyone he cared about, some of whom really were his worst enemies, and we got a sober glimpse of the paradox that is Dexter Morgan.  When Miami’s Assistant District Attorney, Miguel Prado befriended Dexter, we saw in Prado a man every bit as dangerous as he is passionate and every bit as dichotomous as Dexter is.  And of course, there’s Arthur Mitchell, hiding a cold, calculating, and psychotic killing machine beneath the veneer of a churchgoing family man.  Mitchell may have lost the war, but he certainly won the most significant of battles by murdering Dexter’s wife, Rita, before Dexter tracked him down and killed him.

Dexter’s arch nemesis this year?  A handful of indecipherable losers who’ve been inexplicably raping and killing girls together since junior high school.  None of them seem threatening, or even believable.  All but one of them are one dimensional plot devices, while the group’s ring leader, Jordan Chase – a self help guru, no less – is as petulant as Prado was volatile and is as annoying as Arthur Mitchell was menacing.  In Jordan Chase there are no layers to peel back, no contradictions, no redeeming qualities, and nothing to emphasize those qualities in Dexter that we find so intriguing.

However, even at its worst Dexter is still much better than the vast majority of what’s on TV right now.  After 4 brilliant seasons, it’s not surprising that the show stumbled a bit this season.  And despite the shortcomings of Dexter Season 5, it doesn’t change the fact that come next fall, I’ll be planted on the couch every Sunday night to see what happens next to everybody’s favorite judge, jury, and executioner.