The game is based on the anime of the same name.

The story takes place in a city where the hero is a young woman named Diana who is hired by a mysterious man named Bruce to be his assistant. The two develop a bond during the course of the game, which later develops into a love story.

Diana is recruited by Bruce to help him in his fight against the forces of evil, and they eventually form a partnership.

Diana is the only one who knows Bruce's true identity.

Throughout the game, Diana faces many challenges and obstacles, such as an evil man named Jihl who seeks to destroy the city, an organization called the "Agency" who want to control the world, and a group of heroes who want to protect the city.

As the main character, Diana is able to perform various abilities and skills, such as using her powers to create an explosion, use her knowledge of martial arts, and her abilities as a thief, etc.