Two OVA episodes featuring additional stories. Episode 0: Ritsu and Takano used to date back in high school, but broke up due to a misunderstanding. This is that story. Episode 12.5: Hatori and Chiaki go to visit the latter's family. It's really awkward in many, many ways.

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.

[Written by MAL Rewrite]

Straightforward and innocent Hisone Amakasu is a Self-Defense Force rookie stationed at the Air Self-Defense Force's Gifu Base. She was struggling with the fact that she sometimes hurts people unintentionally by her innocent words and decided to join the Air Self-Defense Force, hoping to maintain a certain distance from people. This decision led her to a fateful encounter which profoundly changed her life. It was the "OTF" dragon hidden in the base and it chose Hisone as his pilot. When it soared into the sky with Hisone, her fate as a dragon pilot was decided. It is said that dragons have a key to the future of the world... (Source: ANN)

Hajime Kindaichi's unorganized appearance and lax nature may give the impression of an average high school student, but a book should never be judged by its cover. Hajime is the grandson of the man who was once Japan's greatest detective, and he is also a remarkable sleuth himself. With the help of his best friend, Miyuki Nanase, and the peculiar inspector Isamu Kenmochi, Hajime travels to remote islands, ominous towns, abysmal seas, and other hostile environments. His life's mission is to uncover the truth behind some of the most cunning, grueling, and disturbing mysteries the world has ever faced. [Written by MAL Rewrite]