Manta Okamoto is a strange young man. He is prone to spontaneous tantrums. On the verge of hikikomori, he faces reality through numbers and with a brain full of crisp ideas. He’s also the most creative editor in the magazine where he works, even if he’s always late. One day, one of his seniors at the publishing house offers him a job: he could earn a lot of money just by taking care of a cardboard box for a few days. On the other side of town, a group of gangsters are missing something and will do anything to get it back.
