Snow envelops the 17-year-old Kazahaya Kudou as he struggles to stay conscious in the freezing terrain. Fortunately, a cold-blooded young man named Rikuo Himura rescues him and takes him to his boss, Kakei, who owns Green Drugstore. Out of necessity, Kazahaya agrees to work for Kakei. However, Kazahaya's duties extend beyond stocking shelves and serving customers. Because of his ability to see strange phenomena, Kazahaya is tasked with completing dangerous missions in exchange for payment. Reluctantly paired, Kazahaya and Rikuo—who also appears to have unique powers—must undertake these assignments while facing ghosts from the past that are hunting them.