The Epidemic started when Po-Matoran Trader, Ahkmou, who was working for Makuta Teridax, sold a special type of Kolhii Ball called the Comet to many Po-Matoran. The Comets were popular, but were also tainted by the Makuta, causing many Po-Matoran to fall ill and slowly become infected. Because the plagued had claimed so many, Turaga Onewa was forced to postpone many events such as the Kolhii matches, and carve beds for his afflicted villagers. Ahkmou included the Po-Matoran Hewkii in this illness as revenge for an injury he never actually sustained.
The plot came to an abrupt halt when the wandering Av-Matoran Takua discovered that Ahkmou's Kolhii Balls were the cause of the Epidemic. He and Toa Mata Pohatu found a cave in the Po-Wahi Quarry which Ahkmou used as a depot for the infected balls. Although the cave was guarded by a Nui-Jaga, they destroyed the pillars supporting the roof and buried the Kolhii Balls and the Nui-Jaga in a cave-in. The Po-Matoran afterwards removed all the Comets from the village, and soon the sick Po-Matoran began to recover. Ahkmou then quickly left the village and went into hiding.