"Supergirl" seems like a rather misleading title for this week's episode. 

Even though Kara did return to Metropolis, wielding her powers in broad daylight for the world to see, this episode really wasn't about her - she served merely as the catalyst to force Clark once and for all to face his greatest adversary: himself.

Kara's arrival brought to the forefront Clark's long gestating issues of self-doubt and insecurity, which have been the Kryptonian elephant in the room for seasons now and speak to the reason why he can't fly yet and Kara can.

It's a simple truth, really.  Clark was essentially raised as a human, by parents who did their best to instill in Clark good strong values and a sense of self-esteem, but the absence of true justice in the world has the tendency to blind people to their true potential.  Ever more so would this apply to Clark, as he has abilities that far exceed that of a human.

How could Clark ever truly realize the potential of his destiny growing up within the limited constraints of humanity? Sent to earth as an infant, he has no memory of life on Krypton. Regardless of how much he has learned of his alien heritage, he still stands built upon earthly foundations, and these bind Clark inside an emotional prison, obstructing his transcendence from hero to superhero.

Kara, on the other hand, has no such limitations.  She was already a teenager living on Krypton prior to being sent to Earth as Clark's protector. As such, she was molded by the influence of the people of her home planet and developed her self-esteem based on that ancestry.

 It helps, too, that she hasn't been saddled with the notion of becoming Earth's greatest savior, the way Clark has been ever since first learning of his purpose several seasons ago.  Free from the restraining effects of self doubt, Kara is able to tap into her powers at will.

Therein lies the reason as to why "the darkness" that has come to earth - who fanboys know as Darkseid -  is so dangerous, and why Jor-El tasked Kara to take up the mantle originally destined for Clark.  Darkseid preys on doubt, and can evidently inhabit the body of any being he so chooses, which makes the super-powered Clark his prime target.

It may seem odd that just two episodes ago Jor-El was condemning Clark for having too much pride and vanity, yet now Clark is not fit to embrace his destiny because of his doubts.  Some of the cockiest people I know are also the most insecure. Usually when someone boastfully wears some special ability like a badge of honor for all to see, they're really trying to compensate for their own inner fluctuation and distract others from seeing their imperfections.

I think it's funny, too, that every time Clark expresses his opinion about something, for example tonight in telling Lois - who seems to have no problems with self-confidence whatsoever - that perhaps the Blur should come out into the light, he's always countered with a more compelling argument to the contrary and you can see Clark's overactive inner monologue analyzing every word. 

He questions his own judgment and abilities, and until he can learn to smash the darkness inside of himself as easily as he does steel and concrete, he cannot stand up to Darkseid. 

Fortunately until he can do so, Supergirl is sticking around, (sadly off-screen, it appears) even adopting a flaxen-haired secret identity to battle the raven-infested smoke monster.  There are fewer than twenty episodes left, so hopefully Clark will take that giant single bounded leap sooner, rather than later.

Overall, a strong episode, although I would have liked to have more scenes of Kara being Supergirl.  I also appreciated the reference to Desaad in the title of the club where Lois confronted Godfrey, although I assume this means we won't see an actual representation of Desaad which is a little disappointing.

Browse through a few Smallville quotes from the hour and sound off now: What did you think?

Jeffrey Kirkpatrick is a TV Fanatic Staff Writer. Follow him on Twitter.