The storyline of Megaman Network Transmission takes place during the first decade of the 21st century ("200X"), one month after the original Megaman Battle Network. Following the defeat of the "Life Virus", the ultimate weapon of Dr. Wily and the "WWW (World Three)" organization, Lan Hikari and his network navigator (NetNavi) MegaMan.EXE return to a life of ease. However, no sooner does Lan begin to relax when he hears of a mysterious and destructive computer virus called the "Zero Virus" that infects Navis and causes mayhem via his personal information terminal (PET) e-mail. Lan has other qualms to deal with however, receiving an e-mail detailing fellow NetNavi Roll.EXE being trapped in the internet. MegaMan goes to save her, finding an infected FireMan.EXE as the cause of trouble. Defeating him, the duo talk to FireMan's operator, Mr. Match, and learn of the vaccine being distributed to amend the Zero Virus is actually doing just the opposite, having caused FireMan to go berserk.