Mika, an orphan surviving in a poor area, supports herself by gathering information for the mafia.
Her routine is disrupted when she narrowly dodges a kidnapping attempt by a mysterious figure in black. A stranger steps in, saving her. Grateful for his help but suspicious of his motives, Mika decides to stick with him, eager to uncover his secrets.

"If you're determined to come along, I guess I should at least tell you my name."
"I'm Rad. Nice to meet you, young lady."

[Roughly translated from official website.]