In the year 200x everone has a invetion called the PET. It's a cell phone, computer, textbook, newspaper, and more! On top of that, every PET contains a AI person program called a Net Navi that can do many tasks on a network for his net-op., the owner of the PET. Due to rampant computer viruses, net-op's equip their net navi with battle data, battle chips. The net navis fight the viruses with the battle chip data. This is called Virus Busting.

Cyber City is the next generation of cities. In it, each section of the city works on a different technology. Central Town works on Copybot technology. The other towns also work on other things. However, although this town may seem like the perfect city, it's depths hold a powerful force, the "Cyber Beasts" of legend......

Lan is a kid who had to move from his home in ACDC town to the part of Cyber City called Central Town.His father is one of the world's greatest scientists and creator of net navis. He was called by the mayor of Central Town to work on a project for him, so the family had to move. Lan's best friend and net navi is MegaMan.exe who was created by Lan's Dad. Together MegaMan and Lan defeated the evil Dr. Regal, World 3, Gospel and most recently the evil organization Nebula and their leader Dr. Regal. Now someone else is threatening the world. And what are the "Cyber Beasts" of legend and what powers do they hold? You must find that out yourself.