The Greatest Demon Lord Is Reborn as a Typical Nobody: According to a God

On their way to the class field trip, a mysterious young boy claiming to be a god appears before Ard, Ireena, and Ginny. After making a mysterious request, the god sends the three of them back into the ancient era when Varvatos was active. After deciding to try and gain an audience with Varvatos in order to change their situation, they encounter a woman fighting monsters in a field. Then a figure they all know very well appears before them...