Petey is a bounty hunter in a time and place full of bounty hunters. The criminals are outnumbered by the bounty hunters and whenever a wanted poster is posted, it doesn't stay up for long. Except for one... there's one wanted posted with a negative bounty and no one wants to catch this criminal. But Petey is curious and she seeks the help of a mystery solver...

Follow the lives of Hoshi Yoshimochi, a visual design major student who has problems interacting with people ie seeing people as 'mud masses' who's also not into touching, and her close friend Akari Sonobe, an oil painting major as they go through the ups and downs lives of being art students.