Maurice Hartmann, a Parisian academic, annoys his young mistress with his cynical and disillusioned words and the void of his existence. The proposal of one of his students upsets his life: the young Kiyoshi offers him to taste his assortment of sushi and sashimi. In front of the delighted face of his teacher, Kiyoshi proposes to him to set up a small business of takeaway sushi for busy Parisians. Enthusiastic, Maurice struggles to find funding, and the "Sushi Express" gets off to a great start. But, after a good start, the small business stagnates ...