The nice thing about time-travel story lines is you get to reuse footage. Just ask Robert Zemeckis. The second half of "Back to the Future Part II" is Marty McFly crawling through "Back to the Future."

This time it was John Locke running across himself from the past in the future. It was cool to watch Locke prep Richard to talk to … well … Locke, but it also supports a theory I’ve been worried about most of this season: What if Locke set himself up?

OK, stay with me here. How does Locke know he is supposed to be the leader of the Others? Richard told him. But how did Richard know Locke was coming and would be their leader? Locke told him. Back in the '50s. Which, for Richard, was the first time meeting Locke. How did Locke know that he needed to bring the Oceanic 6 back and die in the process? Richard told him. But how did Richard know? We saw tonight that Locke also told Richard that. Just before Richard came out of the woods and told Past Locke what he needed to do, Future Locke fed him his lines. Time travel, right? Isn’t it fun?

So what if Locke dying and the Oceanic 6 returning weren’t the plan of destiny/the island/Jacob/etc.? Tonight raised the question of whether it was actually all cooked up in that shiny, shaved noggin. John Locke has always felt that his life was meant for something greater. "Walkabout," "Orientation," "Lockdown," "Further Instructions," "The Man From Tallahassee," "The Brig," "Cabin Fever." They’re all about Locke thinking he (or his father) is something greater than he is. And how did every one of those turn out for Locke? At least he’s consistent.

But "Follow the Leader" did give the one piece of evidence that this theory can’t be the case. Locke coming back from the dead? No. The compass. Where did it come from? Richard has had it since the 1950s when he got it from John Locke, who got it from Richard in 2007 right before he traveled back in time. That’s a continual loop, but the compass couldn’t have just spontaneously come into existence. It had to come from somewhere. And if it did just continually go back in time and then exist for 50-some-odd years, wouldn’t it continue to age? It had to come from somewhere. That’s why Locke can’t be his own grandfather. Wait. What was I explaining again?

If all those Lockes weren’t enough for you, there’s another person acting very Locke-ish back in 1977. Jack picks up right where Faraday falls dead with the plot to change the past/present/future all at once. Jack, once he figures out how to get a 12-foot, 40,000-pound hydrogen bomb out of the basement, plans to follow through on Corpsey McDirtnap’s intention to detonate it at the Swan station and pressing the reset button on everything that has happened and basically erasing all the past-season DVDs I bought. That’s how it’s going to be, you know. If Jack succeeds, then all old episodes of "Lost" will change and become about an airplane landing and everyone inside going on with their normal lives. It’s a fact.

No one else seems to be going along for Jack’s ride. Hurley, Miles and Jin are heading to the hills with all the food Hurley can grab. Though first they stop to confess to Dr. Chang about being from the future after they couldn’t come up with the president in 1977. It’s Carter, right? Damn, where’s Wikipedia when you need it?

Sawyer and Juliet buy their subway fare to the mainland with a hand-drawn map (can you use those on Priceline?). I couldn’t help but wonder if this crude doodle by lefty LaFleur becomes the basis for Radzinsky’s blast door map. Radzinsky’s gonna end up spending a lot of time in the Swan station pushing a button, and the more they show of him, the better I feel about that. He was a paranoid lunatic this week. Jeez.

Not even Kate is willing to go blow some stuff up with Jack. “Since when did shooting kids and blowing up hydrogen bombs become OK?” Since always! Come on, Kate. Where’s your spirit of adventure? Where’s that girl who went racing out into the jungle with Flight 815’s transmitter even though she saw the pilot ripped apart by the Smoke Monster? I know blowing up hydrogen bombs and shooting kids are far removed from where they were five seasons ago, but you gotta constantly be taking it to the next level. Eventually, you’ll be jumping out of an airplane in just shorts.

The only person who would follow Jack anymore is Sayid. Though Sayid does admit that be it changing history or killing themselves he’s good either way. Makes sense that after three years plus of all this craziness, one of the survivors of Flight 815 is just ready to call it quits. Sayid is half hoping to ride this bomb like Slim Pickens in "Dr. Strangelove." Though he couldn’t go quietly. He had to question why Jack trusts Eloise, and Jack explains that in 30 years she helps them get back to the island, which starts a whole new time loop I don’t want to get into.

So we’re heading into the season finale. Everybody’s traveling. Locke, Sun, Ben, Richard and a group of Others are heading to Jacob, so Locke can kill him (though part of me thinks Jacob doesn’t exist). Sawyer, Juliet and Kate are traveling back to the real world (looking at the preview for next week, I guess they don’t make it). And Jack, Sayid, Eloise and Richard are traveling to Home Depot, I expect, shopping for tools to build a pulley system of some sort. How are they gonna move big old Jughead?

The real question is: Where are Rose, Bernard and Vincent? Come on. I’ll gladly give up any airtime used to show the Sawyer/Juliet/Kate love triangle to know where they are.

Hopefully, next week.

-- Andrew Hanson

Photo: ABC Studios