What would the world be like without a Superman? Or in the case of tonight's episode of Smallville, what would the world be like without Clark Kent? Well, as often as the question has been asked in comics, tonight we get to see it on television in the aptly titled episode Apocalypse.

The episode begins with Clark reading Dr. Swan's diary and staring at pictures of Lana, trying to decide if he's going to go back in time to visit Krypton before it explodes. He's gotten another SOS from Kara saying that Krypton is close to exploding and that Braniac is going to kill him. He tells Chloe that Jor-El has the power to send him back in time using the Fortress - but that he isn't going. Clark believes that if he allows himself to fade away, much of the harm that befell Smallville won't ever have happened. "This planet will be better off if I never existed," Clark says. Chloe tries to argue and force him to go the Fortress (as if that were possible), but as they are both holding the octagonal crystal, Clark starts to glow and fades away.

Clark then wakes up in his barn, where he is confronted by someone who wants to know why Clark is in "their" barn. When Clark asks who this guy is, he responds "I'm Clark Kent." Somehow Clark gets past "Clark" and goes inside the house where he sees the new Clark in the pictures. Clark is utterly baffled as to how he can be there when his ship never made it to Earth. He tries to get answers from this world's Clark Kent to find out if his friends are ok, but this Clark doesn't know Chloe or Lana.

Clark (the real one) goes into town where he sees Chloe - who, of course doesn't remember him. When Clark asks Chloe if she knows where Lana is, Chloe says she didn't really hang with Lana. Chloe is also happily engaged. Clark is quickly beginning to think he made the right choice in letting himself be erased from this reality.

Clark then goes to the Daily Planet where he sees Jimmy Olsen (sporting his comic-book counterpart's trademark bowtie). After a little not-so-subtle butt kissing, Clark gets Jimmy to look Lana up for him in the Planet's archives. Jimmy finds that Lana graduated from school, studied art history, went to Paris where she met a guy and fell in love - and is now married.

As Clark is preparing to leave he bumps into Lois (quite literally). Lois is somehow still a reporter, even without the Chloe influence, and in fact already has her first Pullitzer. Lois flirts with Clark, and offers to buy him a drink at O'Malley's when a group of Government agents come in to arrest her. Even more oddly, the agent in charge is none other than Kara. Clark may not have come to Earth in this reality, but apparently Kara still did. And in this reality, not only is Kara the head of the Department of Domestic Security, but she was appointed by none other than President Lex Luthor.

Clark is talking to Jimmy about Lex and and Lois and why she got arrested. Lex apparently became President after cleaning up the issue of the meteor freaks - not only was there still a meteor shower, but it was apparently world-wide. Jimmy starts to clam up, wondering why he should tell Clark anything -when Clark shows off a touch of his super-strength. Jimmy was supposed to make a delivery for Lois before she got arrested, and he was about to destroy the package when Clark looks into it. He takes the package to the Ace of Clubs, like Jimmy was supposed to.

At the club, Clark sees former Sheriff Adams, and he discovers that Adams was Lois's informant from the DDS. Adams is distressed to learn that Lois was arrested, and tries to force Clark to leave, but Clark instead gets her to tell him where Lois would have been taken.

Kara leads the agents to a detention center where they are going to process Lois. Kara goes inside, leaving the other agents to guard Lois. Of course, a group of armed guards are no match for one irritated Kryptonian, and Clark rushes in at superspeed, disabling the agents and sweeping Lois (literally) off her feet.

Clark takes Lois back to Jimmy's loft. Lois believes (erroneously) that Clark is a meteor freak, but is grateful for the rescue. When Clark wonders why Lois was taken captured, she says it's because she's in possession of top secret documents. Lex is making the world believe that a domestic group has a nuke. And the DDS was prepared to take him to NORAD. Clark and Lois ponder why Lex would do something that is all but guaranteed to destroy the world. And then Clark sees something on the TV that answers his question. Lex's chief of staff is Milton Fine, aka Braniac. Clark realizes, too late, that if he had been on Earth, Braniac and Luthor never could have seized power.

Clark plans to confront Luthor at a press conference in Smallville. Luthor has a briefcase with the launch codes - if Clark could get that, he could stop the launch. Lois points out that if he goes in there dressed like that, even at superspeed, he'll stick out like a sore thumb. She gives him a suit and a press pass - definite shades of his future self. She looks at him and decides something is missing, and sure enough, in the next scene, Clark is wearing glasses.

At the press conference, Clark uses his super-hearing to listen in on Lex and Kara. Lex is mad that Kara "let" Lois escape, and even accuses her of betraying him. Kara tries to tell Lex that Fine is the real threat, which Lex doesn't believe at all. Kara even shows him the documents from Lois that show that there are no missiles aimed at the U.S. Lex is "disappointed" in Kara, after all that the Luthors did to help Kara after Lionel found her ship submerged in the dam, that she wouldn't have enough faith in Lex to trust him. According to Lex, everything Fine did was according to Lex's orders. Kara is clearly still unconvinced, but tells Lex she'll support him.

After this confrontation, Clark meets Kara in the hallway. He calls her by her name, Kara (which is apparently not the name she goes by). When she wonders how he knows her, he identifies himself as Kal-El. Kara ponders for a moment, then attacks him, stating she was sent to the planet to kill Kal-El.

Clark evades her, telling her that he didn't exist on this planet originally, but now he's here. And the first thing they need to do is get the launch codes away from Lex. Kara scoffs, saying she trusts Lex and will stand by his side. Clark then tells Kara that Milton Fine is Braniac, and that Braniac is manipulating Lex. Clark then says that, together, they can stop Braniac. Kara seems like she may be convinced to listen Clark at this point as we go to commercial.

Lex is in his office, where he is playing with a globe. Kara then leads Clark into the office, where Clark tries to convince Lex that Fine is manipulating Lex so that Fine can get his hands on Earth's nukes. Lex claims that America's best and brightest are already safe. Lex then shoots both Clark and Kara with Kryptonite laced bullets.

Fine leads the Secret Service into the office where he tells the agents to put Ms Danvers into the helicopter. (So now we know what name Kara is using here - her comic book alter ego, Linda Danvers). Fine hands Luthor the briefcase where Lex triggers the launch. Luthor leaves with security to go to the bunker.

Braniac looks down on the wounded Clark, where he says that Kal-El will not stop him from the task he was programmed for. With mankind destroyed, Braniac will get Kara to release Zod, where Zod will possess Lex, and then the two of them will repopulate mankind as a new Krytpon. Fine then shoots Clark in the head, "killing" him.

Before Clark dies, he finds himself in fortress, where Jor-El shows him that all of this was a vision of what could have happened if Clark doesn't go to Krypton and stop himself from being killed. Clark finds himself back in the barn with Chloe, but says there is still time to go back.

We cut to Krypton where Braniac is prepared to stab baby Kal-El. Kara tries to stop him first, but Braniac swats her aside. Clark comes in to make his own attempt at stopping the renegade machine, but Braniac easily defeats him as well, pointing out that Clark has no powers here. While he gloats, Kara stabs him through the back with a shard of crystal. Kara stays behind to handle Braniac while Clark loads himself into the rocket to Earth. Kara tells Clark that Braniac has been destroyed, and the two beat a hasty retreat to the portal before Krypton explodes.

Clark finds himself back on the farm, where he finds that Lana is still as bad off as ever. Kara says that she's certain she destroyed Braniac, but it had no effect on being able to save Lana. Kara tries to convince Clark that they could return to Krypton again, to find a cure, or possibly stop the planet from being destroyed. Clark tells her no - they can't change the past, they can only try to affect the future. Kara promises that, no matter what that future is, she'll always be there for him.

Clark goes to the barn where he finds Lex standing there. Lex wants to offer to help Lana. Clark rejects his offer at first, but then asks if Lex's doctors have any leads. Lex says no, according to "the best doctors in the world", her case is irreversible. That's why Lex is there - if Clark could tell him what triggered the condition, perhaps they could find a cure. Clark, probably wisely, but no doubt painfully, tells Lex that he doesn't know what could have happened to cause Lana to come down with her affliction. Lex says that if Clark "remembers" something he'd like to share, he knows where to find him.

Returning again to the Daily Planet, Clark starts looking for someone who could help Lana. Lois comes in to see what he's doing, and when she sees what's going on, she tries to offer reassurance and help, in her clumsy, Lois-like way. Ultimately, she ends up offering to buy him a drink in an odd reflection of the scene from the "other Earth" scenario.

Finally, we return to the farmhouse, where Kara is getting a late night snack. She goes to the refrigerator and takes out some milk. Suddenly, and with no explanation, she is wracked with pain and falls to the ground. Perhaps due to a "parting gift" from Braniac?

We're closing in on the season finale, and each episode since Descent has had the stakes raised. I can't wait to see what happens next week!