Coming 40 years after the classical Lupin the Third: The Castle of Cagliostro, this film is a new story about a new heroine named Laetitia (Suzu Hirose) and Lupin III. Mostly concerned with Bresson Diary, an item that even the famous master thief Arsène Lupin failed to capture, it is said that anyone who can uncover the secrets of the Bresson Diary will obtain a huge fortune. Having his mind set on this fabulous treasure, Lupin III teams up with a girl named Laetitia with her ardent passion for archaeology. They decide to unravel the mystery of the Bresson Diary together. However, a researcher in a secret organization who has designs on the Bresson Diary called Lambert (Kōtarō Yoshida), and the backbone of this organization, Gerald (Tatsuya Fujiwara), hinder them. What is the astounding truth hidden in the Bresson Diary? Paris, Mexico, and Brazil…An unprecedented fight for the treasure will soon happen on a large scale!