In the world of Gamindustri, four CPUs (also known as Goddesses) battled for supremacy in the War of the Guardians. One of the CPUs – Neptune – was defeated by the others and banished from the heavens. In her fall from grace, Neptune’s memories were lost, but a mysterious book revealed itself to her with knowledge of all of Gamindustri’s history. Joined by Compa, IF, and the sentient book known as Histoire, Neptune embarks on an extraordinary journey across four different nations on a quest to save the entire world!