I wasn't going to post anything about the third episode of Lost's fifth season, but after watching it on Friday in a packed room filled with television journalists at the Television Critics Association Winter Press Tour, I figured I at least had to allude to it.

After all, it's not everyday that you get to watch a brand-new episode of Lost on the big screen, much less one as completely overflowing with neck-snapping plot twists as this one.

Damon Lindelof and Carlton Cuse asked us to respectfully not reveal spoilers about this episode of Lost, entitled "Jughead," especially as the season doesn't kick off until Wednesday evening. So while I won't be spelling anything out for you Lost junkies out there, I will be teasing some details about the shape of things to come.

Let's discuss what you can expect to find in "Jughead."

As much as I thoroughly enjoyed the first two episodes of this season, "Jughead," the third episode completely wiped the floor with me. I was alternately stunned, teary, shocked, and dismayed over the course of the forty-odd minutes that this episode ran. To say that this is a game-changing episode is a bit of an understatement, though not in the way that the flash-forwards or the rescue were. It's more the fact that this single installment answers so many of the underlying mini-mysteries that have kept us wondering for quite a while.

And none of them are spelled out for the audience, either. It's really only after viewing the episode that you'll begin to pull together the puzzle pieces splayed out here to assemble a view on the how's and why's. These mysteries are smaller but crucial elements to understanding some of the characters' motivations and go a long way to seeing where they are right now... and why.

Specifically, the episode deals not with the Oceanic Six (don't expect to see Jack, Kate, Ben, or the others for the duration) but with the characters left behind on the island and the power couple of Penny and Desmond, who makes some interesting discoveries on a life-and-death mission he's been tasked with performing. And we gain a surprising (and poignant) realization about a life-altering event in Desmond's own past.

What else can I hint at about this installment?

• Whatever Jughead may be (I'm not telling), it's absolutely terrifying in its significance and could point at a major plot point yet to come on the series.
  
• You should pay especially close attention to headaches and nosebleeds.
• Some rather familiar faces turn up but in some unfamiliar contexts.
  
• Fumigation isn't always really about fumigation.
• Benefactors are an interesting lot.
• Names can be both poignant and reverent.
• Ipsa scientia potestas est.
  
• A compass is the key to understanding.
  

And, oh, I have a theory that I am just itching to explain to you all but can't until "Jughead" airs next week but suffice it say that it's eating me up inside not to be able to spill my theory, which deals with a new character on the series whom we'll call Blondie for now, though her name is given in the episode. As for what that theory is, you'll have to come back next week but I'm 99 percent certain that I've figured it out.

Ultimately, "Jughead" will answer some long-standing questions while--in true Lost fashion--pose a host of new ones but it's also an episode that testifies to the fact that Damon Lindelof and Carlton Cuse won't be pacing themselves to a crawl to the finale but actually sprinting at full blast. Trust me, you do not want to miss this episode.

Lost's fifth season launches Wednesday night at 8 pm ET/PT with a special three-hour event, including a one-hour retrospective and the two-hour premiere at 9 pm ET/PT.