While attending the 1/1 RX-78-2 Gundam display event in Shizuoka Park, Haru Irei goes to the merchandise section to choose a Gunpla kit. When he fails to pick up the last available High Grade (HG) 1/144 RX-78-2 Gundam kit, he discovers the HG 1/144 GPB-X80 Beginning Gundam and makes it his own. With his newly-assembled kit, Haru participates in Gunpla Battle, a virtual simulation game where players battle each other with their Gunpla models.