It all starts during Operation Impending Doom I. The Irken Invaders were ravaging enemy planets, destroying all species living on them. Unfortunately, one Invader didn't realize he was still on the home planet, Irk. He set fire to a massive space of Irk's surface before he realized he was still on his home, and he tried to put out the fire, bringing disastrous results. This Invader's name was Zim.
            The Allmighty Tallest, the two rulers of the Irken Empire, banished Invader Zim to Food Courtia, to flip burgers for the rest of his days...that is, until Operation Impending Doom II..When Zim heard about this, he quickly left the planet, and hastened to Conventia, the convention planet, to be in the Great Assigning, the event where Invaders are sent to enemy planets to head invasions. When he reached the Tallest, they were mortified that he had left Food Courtia in the first place, not to mention that he was wanting to be in the Great Assigning...but since he insisted, they sent him on a "secret mission" to a "secret planet", just to get rid of him...but Zim didn't know that. They equipped him with the standard S.I.R (Standard Information Retrieval) Robot, or at least that's what Zim thought. In actuality, the Tallest put his robot together out of garbage. When it came to life, it called itself G.I.R., not knowing what the G in his name stood for. Zim thought it was stupid, but the Tallest insisted that "It's not stupid, its advanced!"
            So Zim was sent to the "secret planet", accompanied by G.I.R.. On the way, G.I.R. sang the "doom song", which consisted of the words doom and doomy sung at different pitches...when they finally got there, Zim was almost driven to insanity. After G.I.R. failed to find anything of use while observing the planet ("I saw a squirrel!"), Zim decided to make a house. His ship turned into what Zim believed to be a "standard" human house, and Zim and G.I.R. put on disguises to fit in with the humans. Zim enlisted in "Skool", to learn more about the planet...but in Skool, he meets Dib, the only human that recognizes what Zim truly is...an Invader.....