A cosmic catastrophe permanently altered Earth, draining the world of every trace of color. Humanity transformed as well: the familiar human visage is nearly forgotten in a society now composed entirely of mutants. Set against a gloomy urban backdrop, the lone-wolf investigator Avidia uses his intellect and a unique firearm to track down the planet's remaining hidden fragments of color. He soon encounters a peculiar girl who may possess the key to restoring what the world has lost.