Sanadaya is a small soba noodle restaurant in Makurabashi, Honjo run by Shōbei and his wife. On every fourth of January, the couple only serves Sanada soba from Shinshū. No customers dare visit due to the infamously spicy radish broth that accompanies the soba that day. On Jan 4th, 1789, a man who looks like a wealthy merchant tries the soba, says he missed this specific flavor and promises to come back next year... and so, he does, year after year. Then, one day, Shōbei hears of a tattooed thief from an official, Seizō, which plants a seed of doubt in his mind.