This episode starts out on Mars, with an Irken probe taking pictures of this barren planet.
Meanwhile, on The Armada, the tallests are showing off the newest addition to the Irken Empire, Planet Blorch. Red is telling them that they are going to erase all the structures on Blorch, to make room for maybe Parking Structure Planet, and Purple agrees. But first, Red wanted to acknowlage a special soldier, one of whom without the exile of, the vitory of Blorch and the others to come wouldn't be possible, Invader Zim. Red says without him being exiled, he would be there, screwing everything up. Purple agrees saying that they all know how he screwed up Operation Impending Doom 1, but one guy said that he didn't. Purple ordered him to be seized and thrown out of the air locks. It was done, but Purple said it was the wrong the guy, but everyone got the point. Red ordered cheers for Zim being so far away, when red lights and alarms flashed. Red said that he was reporting in now, and to put it on the main view screen. Zim is dressed as a bear, and Red said that it looked like he was keeping busy, and he said yes, he was in a bear suite. Zim told them that he sent probes out to surrounding planets to search them for potential use, and that he got scans back from planet Mars, and that he would update them when he got more information on the planet. Purple and Red started giggling, and Purple said thank you, without his effort the entire opperation would surely crumble. Zim told them that it would and reported out.
Back on Earth, Zim said that he was amazing. Zim walked into an elevator, and all of the probes came back. The computer updated him on their return, and Zim said told it to begin download. Zim said that the life forms looked un-natural, and whatever wiped out the "marzoids" must have been incredible, almost incredible enough to assist him the annhilation of the humans. Zim called GIR, who was eating muffins and drinking tea with a pig, and told him to meet him in the main launch chamber. GIR tells the pig that he's got to go and he'll see him later, and he flew off the hanger, meeting Zim in the Voot Cruiser, and Zim told him they were going to Mars.
At Dib's house, he is talking to a Swollen Eyeball member, Agent Dark Booty, about cameras being set up on Mars, saying that they have been there for years and NASA finally gave up on them when they couldn't find any life forms, but Dib hadn't. He showed pics of what a regular NASA probe looked like, and then showed a pic of what Zim's probe looked like. Dark Booty tells Dib that he has done well, but he needs conclusive evidence of alien activity before it is confirmed, and reported out.
In the Voot Cruiser, GIR is sleeping on Zim's head, and Zim tells him to get off, and he goes and lays down somwhere else. Zim says that he can almost taste the humans being destroyed, and he says that Mars holds the key, and new words can be invented so he could get off my head. GIR is sleeping on his head once more, and Zim says the taste of human annihilation grows stronger within his head. Zim made it on Mars, and goes off to find out what destroyed the "Marzoids." GIR sees one of the old NASA probes is broken, and fixes it.
On Earth, Dib is trying to convince his dad that they thing on the picture was some freaky alien thing, but he tells Dib that the reason those monitors have been abandoned was because there are no aliens. He tells him that he's been monitering those transmissions since he was a baby with an enormous head, and that it's time to move on to real science. Dib goes to his room and looks at the probes from Mars, four of them, but one is broken. In the last one, he sees a sudden image of GIR, and puts it to full screen, where it is fixed for good once more. GIR starts dancing in front of the camera, but Zim tells him to come where he was. GIR switches the camera to where Zim was standing, and Zim says that Mars was a useless rock. Zim said that they just left the structures there to taunt him, and sees an alien head skull, kicks it, and says he hopes they die, and laughs it off. Suddenly, the structures start to change into one big mobile planet, which Zim gets into the seat of. A big alien head hologram comes on and says that his people worked themselves into extinction making the planet a ship, using the same technology as another near-by planet. Zim asked what the other planet was, and he said that it wasn't important at the moment. Zim asked why he would do that, and the guy said it was cool. Zim started controlling Mars to move somewhere.
On The Armada, Red is telling the people the invader behind the important first vitory was Invader Scooge. Everybody was slightly amazed at this, and the tallest were talking to each other, saying he can't be the poster boy for Irken conquest, he's so short and ugly. Scooge said that as the invader responsible for Blorch's downfall, he to launch the tradition Cannon Sweep, and asked if he was right. Red tells him that there was a new tradition, he gets to be launched as part of the Cannon Sweep. Red snaps his fingers and the cannon comes down, and Scooge gets into the cannon, as they fire him to Blorch. Purple points at the tallest person in the crowd and says that his new name is now Scooge, conquerer of Planet Blorch. Thousands of ships were wiping away the inhabitants of Blorch, when Red and Purple were remenising about the times that Zim has reported. About the time when he called in head to toe in meat, and he almost went blind because the meat invaded his eye sockets, when Zim called in to report. The tallest tell them to quiet down, and Zim comes on telling them that Mars is actually a space ship run my glowing heads, and he is going to drive it into Earth and roll around squishing all of the inhabitants so they can conquer without resistance. Zim tells them to prepare the fleets because he is going to launch the first sweep tomarrow, and signs off. The tallest think this as a joke.
Dib is watching this and he is about to leave, when Professor Membrane askes him where he's going at that hour, and Dib tells him that he knows, and the professor uses a little dummy of himself to ask if he was going to save the earth, and he said yes and ran outside. The professor just said, "my poor, insane son." Dib runs to NASA headquarters and runs past the guarded enterance, and one of the guards asked if that was the crazy UFO kid and the other one said yeah.
Dib runs into the office where Huston is or whatever, and Dib tells them that Mars is a spaceship piloted by an alien, and the head guy asked if it was Zig that he was always talking about, and he corrects him, saying that he activated the face and now he's flying it and said that it sounded really stupid, huh. The guy said yeah, and Dib told him that the giant head said that there is another planet just like it that they modified with giant engines, and they have to find out which one, when a janitor that was emptying the trash looked at Dib. The guy asked what he was fllying again, and Dib pointed at the live martian feeds, but a guy blocked it, saying that he couldn't because they weren't aloud to look at those monitors. The alarms went off and this guy yelled that he thought it was an asteroid, and it was heading straight for them. Dib told them that it was Zim, and just to look at the screens.
In space, Zim is heading straight for Earth, telling them to taste the mighty foot of his planet.
At The Armada, the Tallests were making fun of Zim and Mars.
Back at NASA, Dib walked out of the office, and ran into the janitor. He said that he believed him, and thought that he could help him. The guy said that the other planet with giant engines could only be Mercury, and then pulled out a map, showing the Butt of Mercury, which is lesser known than the face on Mars, but one more mysterious. Dib asked how he could get to it, and the janitor led him to an old room, with a little ship in it. Dib asked what it was, and he said that it was a monkey ship, used to ship monkeys out into space back in the day. He puts Dib into the ship, and Dib asked if it still worked, and he said that he did all the repairs on it himself. Dib asked why he was helping him, and he gave him a hint, that his eyes were swollen, giving away that he was Agent Dark Booty. Dib gets into the ship and launches it out into space.
On Mars, GIR made a little face in the ground from the dirt. Zim was complaining that it was taking too long, and he found some boosters. He told GIR to hang onto something, and GIR hung onto himself. Zim launched the boosters and was going really fast (that's what boosters do, but I couldn't think of anything else). The ship that Dib was in flew past Zim, but Zim ignored it, thinking it couldn't be Dib.
On Earth, the city was being terrorized by people running away. A guy sees Mars heading straight for them, and a guy yells out that they were all doomed, being heard from Mars. Zim was eating a sandwhcih, and GIR was playing around with the steering column thing. The people on Earth stopped to admire Mars heading toward them, but the guy tells them that they were doom, and they started running again. Back on Mars, GIR was eating a sandwhich and Zim was steering. They made it into Earth's atmosphere, and started burning. Zim slowed down to squishing speed, and there was people hiding in gutters. A person almost being squished by Mars, if it hadn't have been for his coke can, and for Dib coming to knock Zim out of the way. Zim told Dib to face the mighty fear of his moons, and shot them at Dib, almost hitting him, but barely missing. Dib moved out of the way quickly, and hiding behind Earth. He finally reappeard and chased Zim near the sun, catching Mars on fire momentarily, and chased each other to Saturn. Zim stopped suddenly, making Dib rearend him, knocking him out of his seat, but Dib was back in it within seconds. Zim told GIR to go take care of him, and GIR went to set beside Dib, pressing buttons and asking what they did, turning on horns and putting it in revearse, and Zim thought to himself that he might not be such a bad evil minion after all, but when Dib told him to go away, he did. Dib got onto him once more, and Zim had the idea to pilot in the asteroid belt. Dib stopped and said that was stupid, and it was, causing Zim to loose control of Mars and making him get in his Voot Cruiser and leave it. Dib told him that he might as well go back to his home planet, because he got the hole thing recorded, but GIR took all of the cameras, damaging some.
Zim reported in to The Armada, and said that his mission was accomplished, he rid Mars of the solar system, and the tallest said they thought he was going to get rid of Earth, but he said they heard wrong, and he was using Mars as a warm-up before Earth. Zim signed off, and they started laughing at him, but in the background, Mars took out almost all of the little ships surrounding The Aramada.