Yasuo is employed as a server at a ramen joint and is romantically linked to the stunning news anchor, Yukiko. However, his financial status is not up to the mark, and when a customer forgets a green jacket, he discovers a means to increase his income. He starts nabbing wallets from people on the busy streets of Tokyo. With this additional income, he manages to buy a fantastic ring for his girlfriend, even though she insists on it not being necessary. With time, Yasuo dedicates himself to becoming Lupin completely. He engrosses himself in every Lupin-related book and movie, and collaborates with Jigen for some time. However, after getting to know about the existence of the much-coveted Ice Cube diamond, Yasuo realizes that stealing it is the only way he can actually become Lupin.