John Connor promises "I'll be back" in this new TV spot for Terminator Salvation, but it's the opposite of Arnie's cocky-robot delivery. Where's he going? A ton of new set reports reveal all. Major spoilers!

The set reports include tons of details, but none is more detailed than the plot synopsis posted by Coming Soon. In a nutshell, the woman who comes to visit Marcus Wright (Sam Worthington) on death row to ask him to donate his body to science is actually Serena Kogen, played by Helena Bonham Carter. And then he's injected with a nasty chemical and apparently dies.

But years later, when John Connor blows up a Skynet communications facility (in that big landing-a-chopper-on-a-Terminator scene), the missile that blows up the facility creates a hole in the ground. Connor swings down the hole on his rope, and fires a flare. There, he sees Skynet machines harvesting bits of humans, including their skin and hair, to make the T-800. Connor sends his men to rescue the humans, then goes back up to chase a fleeing spaceship. But the base gets blown up with all his men in it — thus leaving Connor as the only survivor, making the other Resistance leaders very suspicious. He winds up in a mano-a-mano fight with the T-600 he crashed his chopper on earlier, and finally shoots it in the face. Then he walks off in the rain. Connor gets picked up by a plane and dropped into the ocean, where he sinks to the Resistance HQ, a submarine.

Then a naked man comes out of the crater that Connor left behind, and it's Marcus. He wanders the post-apocalyptic landscape in a daze, seeing how the plants have reclaimed bits of Los Angeles. Marcus tries to talk to someone he sees on the street — but it's a T-600 and he nearly gets killed. Kyle Reese saves Marcus, saying the whole "come with me if you want to yadda yadda" line. They run into a toy factory, and the T-600 is trying to get in. Finally, Kyle drops a heavy train assembly on it, crushing it. Kyle gets Marcus up to speed, but then a Hunter-Killer flies overhead, so Skynet knows they're there. "We need to get out of L.A.," Kyle says.

They go to Griffith Park, where Marcus is able to cobble together a working Jeep from parts of four different vehicles. The radio turns on, and it alerts an Aerostat, one of Skynet's hunting vehicles. Marcus throws a lug wrench and manages to down the Aerostat, but it's already summoned a Harvester. This leads to the scene we saw at Wondercon, where a Harvester attacks Marcus and friends at a 7-11 in the desert. They have a fight with the Harvester's Mototerminators and Hunter-Killer. Marcus decides to take on the H-K to save Kyle and his sidekick, Star. Just as the H-K is about to kill Marcus, Blair (Moon Bloodgood) flies up in her jet and shoots its arm off.

Blair's plane crashes, and Marcus almost drowns in the river, but he crawls out of the river and finds where she's hanging from a power tower. They bond as they walk through the bombed-out landscape, and she offers to take him back to her Resistance base.

And this is presumably the point where Blair's now-famous topless scene would have happened. In another post, ComingSoon describes it: She's topless in the moonlight with Marcus, who is thinking about his past. He asks her if she thinks people deserve a second chance. She says, "You know what I've learned, Marcus? We can focus on what is lost, or we can fight for what is left." Blair also says, "Everybody gets another chance." In other scenes, Marcus says if you point a gun at someone, you'd better be prepared to pull the trigger. And Kyle Reese says they need to get out of L.A. At one point, a thug approaches Blair and says "Woo! She's a firecracker!" and she punches him out. A random resistance woman says, "Life is lived moment by moment. Choice by choice. It's what it means to be human."

In another post, ComingSoon explains that Marcus Wright is a "hybrid," and he has muscle as well as skin over his metal endoskeleton. He has a brain and a heart, and he can bleed and feel pain. He's sort of an intermediate stage between the T-700 and the T-800. He doesn't realize he's a cyborg until two-thirds of the way through the movie.

In any case, Blair takes Marcus to her resistance base, an old missile silo. There's a minefield, but the mines are magnetic and only go off if something metal walks across them — and when Marcus walks past them, they blow up. At first everyone thinks it's just a malfunction, then they see his endoskeleton. Then Marcus is suspended 120 feet in the air, and John Connor confronts him. He has lots of soul-searching. But Blair has fallen for Marcus and believes he's more human than she is, and she busts him out of there. Here's another new TV spot that showcases Blair's faith in Marcus' humanity:

Marcus and Blair are chased by the resistance fighters. And then John Connor's helicopter crashes in the water, and he gets attacked by hydrobots. (This is another scene we saw at Wondercon.) Marcus saves Connor from the hydrobots, and says he can help get Connor inside Skynet. Connor finally agrees to trust Marcus, and readies the troops for a Skynet assault.

John Connor plans a bombing attack on Skynet for 6 PM, but then he finds out his father, Kyle Reese, is held prisoner there. So he decides to go in on his own first, by wrestling a Mototerminator. He rides his captured Mototerminator into the heart of San Francisco, where Skynet is based. Meanwhile, Marcus approaches Skynet's gun turrets, and they scan him and then stand down. He's happy to be still alive, but heartbroken by the reason why. Marcus sneaks past a church full of skeletons, and peeks at a lurking T-600. And Skynet's bulldozer bursts through the church wall, and its tractor treads crush a pile of human skulls.

Marcus finally comes to Skynet itself, which is a huge industrial area, with captured humans being put through a kind of factory where they're hosed off and led forward. Kyle Reese is one of the captured humans being processed, along with his friend Star. He's just telling Star he'll never leave her, when Skynet suddenly plucks him out and lifts him up.

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Also in this facility is Serena's laboratory, which is very high tech and fancy. Marcus gets himself knocked out, and is brought to Serena, whom we haven't seen since the start of the film. By now, he's all shredded and looks more like a machine. Serena says, "Hello Marcus, welcome home," as if he's a son coming home from college. She explains that she was dying of cancer, so she experimented to make cyborg "hybrids" like Marcus, and he was the first of about 108 test cases. We'll see other hybrids along the way. And then Connor gets in there, and there's a huge fight.

At some point, says ComingSoon, our heroes fall out of Serena's lab and into the Terminator factory, where they land on a pile of metal Terminator skulls. And then their eyes light up. And there's a flooded underwater tunnel, where a T-100 surprises Connor and Marcus by rising out of the water. There's also a "mutant forest" at some point in the movie, according to designer Martin Laing.

Presumably somewhere around this time, we have the scene Slashfilm describes, where a bruised and bloody John Connor falls to the wet pavement of Skynet's Terminator factory. John lifts a huge gun and fires, causing an explosion above. But he's still being chased by something, and he drags himself along the floor, then shoots a smaller gun, causing a cloud of smoke. Also, Slashfilm says the movie's code title "Project Angel" actually references a major plot point in the film.

And according to the L.A. Times, that second meeting with Serena Kogen, in her lab, is what leads to the startling ending that McG says will "shock everyone."