When the princess is born in certain small country "Archang", she became a member of an elite unit that protects the country "Princess Knights", there was a legend to protect the country from the nearby demons. The eldest daughter Scarlet is now a commander because of her ability.

A certain day, younger sister princess knight Esuteru as an enlistment test, is facing the dungeon that is a orc's nest. However, it became the brothel of an unexpected orc.