The protagonists, Tachibana Kazuki and Kagura Kyouka, are childhood friends.

While taking shelter from the rain at an old temple, the two are greeted by a young girl from the temple, Fudou Shinra, who invites them to play a game.

The game begins happily with Matsudaira, who seems to be an acquaintance of Shinra, joining in, but Shinra says, "You can't go home until you reach the goal."

Unable to find a exit, Kazuki gives up and draws a lottery ticket for the game, but this time he gets a pink card.

Seeing the color, Shinra chuckles, saying, "This is getting pretty interesting..."

In this mysterious space, a wave of erotic events is about to begin!

[Translated from the the official site, archived]