Earth and Its Impending Doom

Prologue:

He was staring from the cracked window of Tak's ship, looking down at the sorry remains of his former home. How could this of happened? Wasn't Zim supposed to be an Irken failure? Wasn't he supposed to be the most patheticly incompetent Irken there ever was? This isn't what was supposed to happen. It should have turned out differently. He could remember what had happened like it was yesterday, but in truth, it happened today, only today two years in the past. It was May 17, the horrible day everything went wrong.