The story takes place in Tokyo Butei High School, a special school where armed detectives—Butei—are trained to use weapons. Kinji Tooyama is a second-year-student who has a special ability, but he keeps it a secret to maintain an ordinary, peaceful life; however, when he gets caught in a bombing on the way to school, he encounters H. Aria Kanzaki, the most powerful S-Rank Butei student in Assault Studies. (Source: ANN)

After preventing Japan's destruction, Akira Takizawa made one final request to become the King of Japan, before he erased his memories once again and disappeared. Leaving Saki Morimi with his cellphone, the only clue she has in regards to Akira's whereabouts is the message, I'll be waiting where our journey started. Six months later, rumors have spread about Akira, and Saki's search leads her to New York City. However, Saki is not the only person who goes to investigate—with several billion yen burning a hole in their pockets and a challenge to save Japan, the remaining Seleção are not far behind. Some are willing to help Akira achieve his goals, but a few are making dangerous moves in order to eliminate him and achieve their own picture of a better Japan. With rising stakes and new revelations, the game is still on.

On November 22, 2010, Japan was hit by missile strikes, a terrorist act that fortunately did not harm anyone, becoming known as Careless Monday. Quickly forgotten, society goes on about their lives as normal. During her graduation trip to America three months later, friendly college student Saki Morimi's life is forever changed when she finds herself saved from unexpected trouble by Akira Takizawa. Takizawa is cheerful, but odd in many ways—he is stark naked and suffers from amnesia, believing himself to be a terrorist. In addition, he possesses a strange cell phone loaded with 8.2 billion yen in digital cash. Despite Takizawa's suspicious traits, Saki quickly befriends the enigmatic young man. However, unbeknownst to her, this is the beginning of a thrilling death game involving money, cell phones, and the salvation of the world. Higashi no Eden chronicles Saki's struggle to unravel the mysteries behind her savior, while Takizawa himself battles other individuals armed with similar cell phones and returning memories which reveal his possible connection to the event from months ago.

A series of 3-5 minute specials that were bundled with the HighSchool DxD DVD and Blu-rays. They are a stand alone set of episodes that are not a part of any story line in particular. Special 1: Going Sunbathing! - The Occult Research Club goes on a beach outing. Special 2: Issei's Private Training! - Issei is being given lessons in magic by Akeno. Special 3: A Little Bold, Koneko-Chan... Nyan! - Koneko accidentally has her personality reversed magically, making her incredibly sexually active and reversing her sexual preference. Special 4: The Untold Story of The Dress Break's Birth! - A few flashbacks of how Issei first found out and eventually perfected his special move, Dress Break. Special 5: Making Udon! - As part of a penalty for losing a bet, Sona and Tsubaki make udon for the Occult Research Club but the udon comes to life in a peculiar way... Special 6: Asia Transforms! - Asia wants to prove she is just as bad as any demon by using ideas found in Issei's magazines, going as far as dressing up like a harlot and seducing him. (Source: Wikipedia)