During the day, Meimi Haneoka is just your average 14-year-old, but come nighttime, she's known as Saint Tail. This modern-day Robin Hood steals from the corrupt and restores their ill-gotten gains to their rightful owners, with her accomplice, Seira Mimori, a friend who is training to become a nun. However, Daiki Asuka (also known as Asuka Jr.), a fellow classmate, is hot on her tail and may soon become her romantic interest.