Best Mystery Anime of 1991

In "City Hunter '91," Ryo Saeba continues as the City Hunter, a "sweeper" working in Tokyo's streets. With his partner Kaori Makimura, they handle cases for people in desperate need of assistance. While Ryo uses his excellent marksmanship to fight crime, he also has a weakness for beautiful women. Kaori must keep his ecchi tendencies in check using her giant hammer.

To the casual observer, Maki, Reimi, and Yuka hardly seem like top-notch crime fighters—which is probably why they're stuck handling traffic duties instead of more thrilling police work. But everything changes when Yuka is abducted by a white slavery ring run by a businessman with political connections, leaving the rest of the police too intimidated to act. Now Maki and Reimi have no choice but to slip into skintight battle armor, commandeer a tank, and teach that slaver that if you play with fire, you'll end up getting your own ass burned.

A full three years have passed since Gargoyle and Neo-Atlantis were defeated, but now a fresh threat emerges in the form of Geiger. This new foe wields advanced robotic technology and plans to spark a global war, then take control amid the resulting turmoil. Once again, Nadia and Jean are thrust into action, striving to keep the world from bringing about its own destruction.

According to the legend of Mermaid Forest, consuming mermaid flesh grants immortality—a reality Yuta, who has lived for five centuries, and his companion Mana know from experience. Yet most who attempt to gain this power either perish or become grotesque beings. Fifty-five years ago, Towa Kannagi received mermaid blood from her sister Sawa to cure a life-threatening illness. This left Towa eternally youthful except for her snow-white hair and a monstrous arm. Over the decades, she has longed to restore her body to normal, relying on blood transfusions from deceased youths with the help of Dr. Shiina. One day, Mana is mistakenly pronounced dead and taken to Towa for a transfusion. Realizing Mana is still alive, Towa must decide how far she is willing to go to heal herself. Can Yuta save Mana before it is too late?

The last occasion Saki left a school was to swap her school uniform for prison attire, but when federal authorities required someone to penetrate a merciless crime syndicate operating inside an elite high school, they decided they required the most formidable bad girl available. Now Saki is back on the streets for a decisive final exam, equipped with a concealed gadget that merely appears to be a yo-yo, and permitted to employ any level of force to accomplish her mission. Saki is charming, dangerous, and prepared to risk everything—since if she fails this assignment, her next garment will be a body bag.

Lupin takes part in a dangerous car race stretching from Madrid to Paris. The ultimate reward is Napoleon's dictionary, which contains the key to the Treasure of the Empire—an object desired by numerous parties. Accompanied by his companions, Lupin vies for the prize while being chased nonstop by Inspector Zenigata and various international secret agents. Vintage cars and modern weaponry amplify the thrill and peril of the competition.

The Ryudo brothers possess the remarkable speed, strength, and abilities passed down from their dragon ancestors, powers that grow stronger with time. When placed under intense stress, they can transform into savage, uncontrollable dragons. As their skills develop, they draw the unwanted attention of dangerous foes, including secret organizations with endless resources and cutting-edge technology who will stop at nothing to seize control of the brothers.

Mizuki Ichijo, a junior at Kosen High School, becomes involved in a string of supernatural and puzzling incidents at her school, ranging from accidents and suicides to bullying and romantic troubles. Since her grandmother works as a medium, Mizuki is in a special position to look into these occurrences. She grows close to upperclassman Meiko Tsukikage, and together they try to solve the mysteries haunting their school.

After moving to Paris, Antoinette—known as Tony to her friends—starts working as a reporter for La Voix de Paris. Together with her colleagues, photographer Alain and artist Bricolage, she investigates a variety of mysterious cases. Her drive for justice frequently pits her against the villainous Madame Lapin.

The manga Princess Connection, originally serialized in Betsukomi Flower Comics by Kazumi Ooya, centers on a mostly male pop group that also functions as a detective agency. Their tranquil daily life is shaken when someone from one member's past returns and causes trouble, eventually resulting in the abduction of the group's only female member.

In "My Sky: Detective Story," the main character Yasuda Ippei—voiced by Shonozaki Ken—is the child of Yasuda Seijiro (played by Osugi Ren), who serves as the chairman of the massive Yasuda Group. Born into a high-status family, Ippei demonstrates no flaws and earns the respect of those around him. With exceptional academic ability, he finishes high school in two years and gains admission to Tokyo University's Faculty of Law without sitting for entrance exams. Seeking to cultivate his own personal sense of justice, Ippei declines his inheritance from the Yasuda Group and enrolls in the police academy instead. Working as a detective at Kyobashi Police Station, he confronts serious criminal threats with bravery and persistence.