Yasuo, employed at a ramen eatery and romantically involved with the lovely news anchor Yukiko, faces financial struggles. Discovering a forgotten green jacket left by a patron, Yasuo ventures into the bustling streets of Tokyo where he resorts to pickpocketing to boost his income. With his ill-gotten gains, he surprises Yukiko with a lavish ring, despite her protests. Gradually consumed by his fascination with the infamous Lupin, Yasuo immerses himself in Lupin-related media and collaborates with Jigen. His fixation intensifies upon hearing about the coveted Ice Cube diamond, believing its theft will solidify his legacy as the true Lupin.