Arsène Lupin III is the grandson of world-famous thief Arsène Lupin, and he's living up to his grandfather's memory as a high-profile thief himself. Due to his infamy, Lupin III attracts the attention of the persistent Inspector Zenigata of the ICPO, as well as rival criminals. Lupin III's criminal lifestyle even seeps into his love life. The main woman in Lupin III's world is femme fatale Fujiko Mine, who Lupin III can never tell is working with or against him. Follow Lupin and his gunman partner Daisuke Jigen on their quest to own the world－or at least the valuable bits!

Arsene Lupin III discovers that the spoils from his latest casino robbery are actually Gothic Bills, legendary counterfeits that are nigh impossible to distinguish from genuine bills. Together with colleague Daisuke Jigen, he heads to the small nation of Cagliostro to investigate the origin of these counterfeits. Upon arrival, they save a girl from a high-speed chase who turns out to be Clarisse d' Cagliostro, the daughter of the late Duke d' Cagliostro. She is running from a sinister plot by Count Cagliostro to steal her family's treasure through a forced marriage. Natural flirt Lupin dislikes seeing a girl in distress and seeks to remedy the situation. Goemon Ishikawa XIII, Fujiko Mine, and Kouichi Zenigata also join the fray, each with their own motivations. As everyone converges at Cagliostro Castle, Lupin reminisces about his visit there 10 years ago, and the castle's secrets emerge from the depths.

Many people are falling prey to a suspicious new religion. Lupin III infiltrates this group, hoping to steal the treasure their leader keeps hidden. There he lays eyes on the beautiful, bewitching woman who has the leader enthralled. This is the story of how fashionable female thief Fujiko Mine first met Lupin III, the greatest thief of his generation. (Source: ANN)

It is a cross over between the series Lupin III and Detective Conan and takes place after the television special Lupin the 3rd vs Detective Conan. The plot follows Conan Edogawa who sets out to apprehend Arsène Lupin III, the suspect of stealing a jewel called Cherry Sapphire. (Souce: Wikipedia)