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!