This episode starts out with Zim reporting to the tallests, saying that his base is absolutley impenetrable, when a little kid starts walking around behind him. Purple notices him and askes who the little person was, and when Zim turned around, the kids mom came up to him and told him that she told him not to wander around. Zim hurridly tells them he'd call them back later, and cancels the connection. GIR is watching TV, and Zim tells him they're going down to the main system core, and that the trouble can only mean a defective artifical intelligence brain, and that he'll have to replace it. GIR replies by screaming about tacos.
Down in the lab, Zim tells him that his plan is simple, all's he has to do is moniter the download, while he replace the old A.I. (artificial intelligence) brain with the new one. GIR is still replying with taco. Zim tells him that alls he has to do is watch for any fluxuation in the download, and GIR is spacing out. Zim tells him to pretend that it's a taco. Zim tells him that if there's any changes in the taco beam to let him know. Zim goes to replace the brain, and GIR takes out a rubber moose from his head. GIR is playing around with the moose, but it flies out of his hands, past the "taco" beam. Zim tells GIR he is about to install the new brain, but GIR is trying to reach for his moose, trying not to touch the beam. Zim put the brain in, send all kinds of waves and stuff to the beam, but GIR interferes with the beams. The machine malfunctions, and Zim goes to GIR to ask what he did, but GIR is turned off. Zim touches GIR, but he falls on his face. Zim concludes that he is broken. Zim tells him that he has to go get another brain for the house, and then he'll fix him. Zim tells the elevator to take him to the storage level, but it doesn't do anything. Zim tells it to do it again, but GIR's voice tells him to say please. Zim tells GIR to quit messing around, that they have to get the house back online, but GIR asks where his moose was. Zim asks GIR if he was the new brain, and he said that he guess's so, and Zim told him to get back into his old body. GIR makes some noises, and then tells Zim that he can't. Zim looks at the data beam and concludes that it is damaged. He tells GIR that he'll have to stay in there until he can fix it. GIR uses a mechanical hand to play with the moose, and Zim tells him that he needs to concentrate, that there defenses were... but GIR tells him that he's boring. GIR picks Zim up and ties to squeeze him like the moose, but Zim breaks free. Two more robotic hands come after him, but Zim prys open the elevator before GIR can grab him again.
Inside the elevator, GIR is doing fake elevator music. Zim tells GIR to take him to the equipment room, but GIR tells him to do a little dance. Zim tries to fight him, but GIR brings down a larger speaker, and Zim has no choice but to dance. The elevator starts to go up, but it goes up too fast and he's in the kitchen. Zim yells at him, but GIR messes around with the blender and the oven. He says that he's going to make toast, and a toaster comes from the ground and spits toast at Zim. GIR tells Zim that he's sad, and that he knows what will make him fell better. Zim tells him that he would feel better if the house was back to normal and if he would listen to him for once, but GIR tells him that he could use some of this, and pulls in about 10 TVs with different cartoons on them. Zim says that he'll wear himself out eventually, and he'll just wait.
One year later, GIR is still messing around with the TVs and the house. Zim finally goes crazy and yells for GIR to let him down to the lab so he can make everything normal again. GIR sends him a TV with a commercial for the Krazy Taco. The Krazy Taco man says the the drive thru is open all night, and GIR says that he must obey the taco man. The house starts to move around, and it transformed into a giant dog. GIR starts running toward the Krazy Taco, and he starts yelling that he's going to get him some of those tacos. Zim tells GIR that the base is being exposed, and they should go back while they are un-noticed. GIR ignores him.
A man is at a pay phone talking to someone about his new car, saying he's going to drive around all night, and then drive around some more util it's his some more. GIR comes running and smashes the car. The guy on the phone calls the police and reports a giant house coming from the sky and destroying his car. In a police car, the radio says to be on the look-out for a mobile home rampaging around the area, and one of the cops asked if mobile homes can rampage, and the guy replied that it must be a new one. GIR narrowly misses that cop car, but is followed by 10 others. Zim tells GIR that tacos are not worth runing the mission for, and that he should stop now because he's his master. GIR stops and says that he's right, he'll get a giant burrito too. GIR runs into a truck that says gas on it, and then knocks down a light, causing a fire and a big explosion, making the cops back down. The same cop from Walk of Doom yelled to get him.
GIR takes finally makes it to the drive thru, and the guy runs back his order, "two large tacos, a burrito, and a medium GIR take us back to the base right now," and askes for a drink. GIR askes what kind of drinks they got, "a new poop, classic poop, diet poop, cherry poop with salty lemonade." GIR asks for a large classic poop. Zim hears the cop cars and gets scared. The man tells him to drive thru the next window. GIR tries to cawl under the taco shell, but brakes it. The guy gives Zim the tacos and tells him to have a nice day. Zim throws money at him and tells him to shut his noise tube. Zim tells GIR that he's got his tacos, and he tells him to give them to him, and he says that he needs the tacos or he will explode. He tells GIR that he will give him the tacos, but he has to take them back to the base. Meanwhile, thirty cop cars try to block him. GIR runs over the cars, all except for three, and jumps over the mall, leaving the cops to run into the mall.
They finally make it home, and GIR has got a taco in his robotic hand, but he can't find his mouth. Zim tells GIR that he needs to cooperate and that they need to fix the mess and get the house back to normal. GIR hands over the taco, and Zim tells him to take him to the equipment room.
Zim is back reporting to the tallest, while GIR is in the background eating tacos and a crazy taco hat on. He tells them that there was a few minor glitches here and there, but everything is back to normal, if possible, more normal than they ever were.