It is difficult to stand out at a Ginza club where every hostess wants to be number one. It is competitive. One of them is a virgin and also just eighteen years old. She wants to become the number one hostess to help pay the bills for her family. She advertises herself as 'virginity for sale.' It is an auction and the prize goes to the highest bidder. She doesn't have hostess skills however. The club's manager was the number one hostess in all of Ginza and helps the younger woman.

Misaki Miyasaka, a transfer student, who joined the Hanayama Gakuen "Undressing Mahjong Club". She has a special ability to see the character's role when she reaches sexual cum during Mahjong. One day, Misaki and his friends are going to challenge the undressing mahjong game against the yakuza to protect the peace of the school. The second series of "Ura Mahjong Mijin Retsuden" series presented by Gambling x Dense Eros.