Nana is married to her husband and is living a happy life. - One day, Nana was invited on a trip by her husband and came to a certain inn. - With a pleasant landlady and a clean room, Nana was supposed to enjoy some rest with her husband, which she had forgotten about for a while... - But tragedy strikes. - A gambling hall called Tetsugamkai is held in secret at the inn. - Isn't your husband going to be there? - Moreover, the tragedy doesn't end there; Nana turns pale when she hears the rules of the Tetsugamkai.