Several years after preventing Arfoire's revival, Gamindustri has remained at peace without any major issues. The CPUs and their younger sisters have been enjoying their quiet lives for a while... Then one day, the CPU of Planeptune—Neptune—is sent to another dimension. This new dimension feels very much like her own...except it has only progressed to the Gamindustri of the 1980s. In this dimension, a group of villains calling themselves the Seven Sages are trying to create a world without CPUs. With help from her new friends, including that dimension's CPU of Planeptune—Plutia—Neptune begins her quest to protect a totally different Gamindustri in her brand-new adventure!