The protagonist is Yurinas, the god of Boobjobs that lives in the underworld. However since nobody builds effigies of him, his rank is low. He wishes to heighten that rank and become intimate with the goddess Athena who is famous for her huge bust but things aren't so simple.
One day while enjoying some sword play like always with his friend Faron, the god of Death. He pokes a strange protuberance on a rock and gets sent to the human world.

When he wakes up Yurinas realizes he is in a remote forest of the Romania empire and that he is trapped there. To escape he must have effigies of him built and gather up some power.
While thinking of a way to get out, some men from the breast massaging tribe arrive. They seem to think Yurinas is a demon and came to eliminate him. However a woman with snakes instead of hair then shows up from inside the forest and turns some of the men into stone.

The men, terrified of the snake woman, decide to ask for the protagonist's help, judging it necessary even if he was a demon. So they build a statue of him which gives strength to Yurinas, making his escape possible.
"Demon-sama, please eliminate the monster from the forest"
Yurinas has them build effigies of him in order to face the monstrous woman.

[Translated from the official site]