In the time before time, there was a great and industrious city called Ghetta Nui. Four legendary Toa were sent to protect the city from darkness. Little did they suspect that darkness would come from within. Despite the Toa's efforts to convince the matoran of Ghetta Nui to slow down production so as to reduce pollution and conserve resources, the matoran would not heed the Toa's warnings. Instead, the matoran turned against one another and their Toa protectors, hording what little resources they could obtain for themselves. One by one, the Toa were defeated by the gangs of matoran that they worked so hard to protect. Now their once-great city is sullied and tarnished by bigotry, violence, and pollution.
On the island-city of Ghetta-Nui, industry has ravaged the rescources to a point where poverty and petty crime is commonplace. Gang wars have separated the city, and all the gangs are constantly fighting over Ghetta-Nui's dwindling rescources. Seeing their misfortune, the Great Spirit sent five toa to protect the matoran of Ghetta-Nui... from themselves.