Kamasutra (manga)

Prof. Isamu Aikawa is researching the location of an ancient Indian princess, Princess Surya of Gupta Empire. Prof. Aikawa's grandson, Ryu, becomes involved with the research when a group of gangsters attacks Ryu and his spoiled girlfriend, Yukari, and ransacks his grandfather's apartment in search of information about the princess until he discovers the manuscript, which was an ancient Indian sex manual called Kamasutra. Ryu travels to India to help his grandfather, where he meets his grandfather's assistant, Shakti, and adventurous Indy Yakko, who introduces him to the techniques found in the "Kamasutra."

On the way to Prof. Aikawa's location, Ryu and Shakti, are kidnapped by the same gangsters working for the Naga Tribe—an ancient Indian cult who are also seeking the princess for their own intentions—and are soon taken to the Palace of Naga. Ryu is sexually drained and physically debilitated while in captivity, but his grandfather and Yakko manage to rescue them. To search for Surya's whereabouts, Prof. Aikawa's group goes to Khajuraho Temple to find a Holy Grail-like artifact called the Sex Grail, which holds the key to eternal life and is sealed inside Rama's sculpture. With it, they can locate and retrieve the frozen princess Surya, who was resting at the Himalayas, using the grail to revive Surya from the suspended animated state.

Meanwhile, having failed at obtaining the grail, the leader of the tribe, the Old Master, dies, and his son, Prince Rudra, assumes the leadership, and sexually assaults Jody, the Old Master's nurse, in cold blood. He then personally kidnaps Surya to obtain her love juice and then tries to obtain the grail by manipulating Ryu into an exchange of the princess for the grail. After obtaining the grail (and kidnapping Ryu in the process), he sends his henchman, Hige Godzilla, to trick Yukari into raping Surya for them, which she does, and is also captured and jailed along with Ryu before they are crushed and stuck by a wall trap. Yakko, however, can track them down and rescue them. While trying to escape, they're confronted by Rudra, who uses his mystical power to attack them, but they manage to escape nonetheless.

Prince Rudra is now in possession of the Sex Grail in an attempt to gain immortality himself and is forced to marry Surya. However, during the wedding ceremony, they're interrupted by the arrival of Captain Austin, an American soldier and Jody's father, who stages an invasion against Rudra to avenge his daughter. He manages to escape along with Surya and the grail through the Boat of Garuda, where he opens a portal to enter them into the earthly paradise of Shambhala, which is hidden inside the waterfall. He is soon followed by Ryu and Yakko with the help of Prof. Aikawa and Captain Austin. As they entered Shambhala, Ryu and Yakko found a giant golden egg-shaped vessel, the Space Egg, floating like a sun, and they continued to rescue Surya.

In the meantime, Prof. Aikawa goes to Khajuraho once again to find another way of entering Shambhala along with Shakti, Yukari, and Prof. Aikawa and Hige, by using the grail counterpart, the Cup of Death, and joining them in a foursome position, which is similar to Khajuraho's erotic sculpture. As Prince Rudra and Princess Surya enter the Space Egg, Prof. Aikawa and his allies (who are shown naked in a foursome position) appear before them. Soon after, Ryu and Yakko also arrive, and Ryu manages to catch Rudra just as he enters the egg with Surya, in which the grail falls outside the egg, just as the Space Egg elevates itself and flies towards outer space.

Rudra and Ryu engage in the fight, only to be interrupted by the group of celestial angels who challenged Ryu and Rudra with a final task to perform in group sex based on the Kamasutra, as only one can be together with Surya. Ryu decides that he wants to do it with her, leading angels to execute Rudra by a Nāga-like creature and kill him before being dragged out of the egg, leaving Ryu and Surya to have sex in eternal pleasure as the angels disappear. Having fulfilled its purpose, Space Egg split into two vessels, separating both Ryu and Surya.

At the same time, Prof. Aikawa, Yakko, Shakti, Yukari, and Hige manage to get all of them back from Shambhala to Earth using the Boat of Garuda with the help of the Sex Grail. As they return, Prof. Aikawa's group sees the two Space Eggs fall to Earth; one falls into a river, where Ryu is released, while Surya remains inside the other, floating in the sky. Surya fulfills his promise to expect their child, puts herself into an eternal slumber as the Space Egg gets smaller and attaches itself to the Grail. Afterward, the next day, the Sex Grail and the Space Egg are now returned to their original place and sealed into the sculpture, while Ryu and his group leave India and return to Japan safely.

• Ryu Aikawa (阿井川 竜, aikawa ryū; played by Yasunori Matsumoto): The hero of the story, a handsome but sexually inexperienced young man. During the course of the story, he is taught in the Kamasutra so that he can conquer the final task. In the anime, he is the reincarnation of Gopal, a knight who protected princess Surya.
• Princess Surya (スーリャ姫, sūrya hime; played by Sakiko Tamagawa): An immortal ancient Indian princess who holds the secret of eternal life. In the anime, she knows Ryu from his past life.
• Prince of Naga (ナーガのプリンス, nāga no purinsu; played by Jurota Kusogi), also known as Rudra (ルドラ, rudora) or Rudrasin (ルドラシン, rudorashin): The main antagonist after the death of the Old Master, he seeks to obtain the Sex Grail and kidnapping Surya as his bride in order to achieve eternal life. He was a Navy Lieutenant until he assumed the role of leader of the Naga Tribe. In the anime, it is implied that he is the reincarnation of Ryu's killer.
• Shakti (シャクティ, shakutei; played by Naoko Matsui): Prof. Aikawa assistant and lover. She is the first to introduce Ryu into the art of the Kamasutra. Her real name is Irene Adolfo
• Prof. Isamu Aikawa (阿井川 勇博士, aikawa isamu hakase; played by Kenichi Ogata): Ryu's grandfather and the archaeologist behind the discovery of Princess Surya. In the manga, he constantly engages in sexual acts with Shakti.
• Yukari Tsuji (辻ユカリ, tsuji yukari; alternatively written 辻ゆかり in the OVA, played by Chieko Honda): a spoiled yet sassy girl who is Ryu's girlfriend.
• Indy Yakko (インディやっこ, indei yakko; played by) Masami Kikuchi: A self-proclaimed adventurer who is a parody of Indiana Jones and comic relief. He successfully helps Ryu during the course of the story. His real name is Hiya Yakko.
• Hige Godzilla (ヒゲゴジラ, higegojira; played by Naoki Tatsuta): The character from the Yadamon manga and Harenchi Gakuen. In this story, he is helping the Naga tribe and acts as the main henchman/servant of the prince.
• Old Master (老師, rōshi; played by Ikuya Sawaki): An ill, disfigured old man with a snake-like voice, and the former leader of the Naga Tribe who is seeking the secret of the "Sex Grail" and ancient Princess Surya. He is the father of the prince and is also called Beshuma.