In a world invaded by a "rust" virus, human emotions are being ruthlessly stripped away, and the infected will eventually become "empty shells" without thoughts. In order to curb this emotional plague, everyone is forced to wear emotional suppressors, and the world turns into a dead gray.
However, beneath the depressing surface, there are still souls that are unwilling to accept this and are secretly surging. Young Finn is a model citizen who follows the rules during the day, but at night he is a sneaky scavenger in the secondhand market. He risks being discovered and secretly collects old objects that can arouse weak emotions - a faded brooch, a damaged piece of music. These are his last weapons against the assimilation of the world. When his beloved sister was unfortunately infected with "rust" and her life began to count down, Finn resolutely stepped into the forbidden place.
He took the initiative to contact the legendary underground organization "Color Pickers", a group of light chasers dedicated to finding the legendary "emotional spectrum" that can cure "rust". Here, he met the mysterious and cold girl "Zero", who seemed to have a different understanding of emotions than ordinary people. Under the guidance of the "Color Picker", Finn and Zero embarked on the thorny road of searching for the "emotional spectrum". Not only do they have to face the pursuit and interception of "empty shells", but they also have to be wary of the ubiquitous defenders of order.
