Gunpla Battle Nexus Online (GBN) is a new network game that lets people enjoy a variety of missions using Gunpla in a virtual cyberspace dimension. Middle-school students Riku Mikami and Yukio Hidaka recruit their classmate Momoka Yashiro and dive together into this vast world. Becoming "Divers," or inhabitants of GBN, they meet a mysterious girl named Sarah who has an amazing sensitivity to Gunpla. They begin playing alongside her, but...

There are many other famous Divers, starting with Kyoya Kujo, the champion whom Riku admires. Multiple Divers can join to form a team called a "force." Meanwhile, the game is disrupted by Mass-Divers who use unofficial tools called break decals. Through many encounters and experiences, Riku and his friends will build not only Gunpla, but their own adventures as well!

(Source: Gundam Wiki)