Though it feels petty and humiliating, Park Mu-an, a useless salesman with no friends, no lover, and no hobbies, grinds through each day, haunted by the sense that he's growing older without achieving anything. His only comfort is a bowl of onion soup at a small restaurant after work. On the hardest nights, one warm, sweet spoonful gives him strength to face tomorrow. Then one day, it disappears from the menu. Why? He has to find out.