Riku Mikami and Yukio Hidaka, two middle-school students, recruit their classmate Momoka Yashiro to join them in Gunpla Battle Nexus Online, a network game that allows players to control Gunpla in a virtual environment. In GBN, users can form teams, known as forces, and compete against other players. They meet Sarah, a girl with exceptional skills in Gunpla customization, and begin to participate in the game with her guidance. The game's competitive scene is led by Kyoya Kujo, a skilled player Riku looks up to.