In the distant future, in a tropical city on the ocean, fifteen-year-old Mizuki Maia is expecting to be accepted into the prestigious Ocean Agency after acing her entry exams.Even getting caught up in a shootout, as a bystander, between two bikini-clad young women on scooters (part of the Nereids Kamchatka branch as it turns out) and some gunmen, does not phase Maya much. But when she returns home things start to go very wrong...

In the distant future, in a tropical city on the ocean, fifteen-year-old Mizuki Maia is expecting to be accepted into the prestigious Ocean Agency after acing her entry exams.Even getting caught up in a shootout, as a bystander, between two bikini-clad young women on scooters (part of the Nereids Kamchatka branch as it turns out) and some gunmen, does not phase Maya much. But when she returns home things start to go very wrong...

The story is set slightly in the future and revolves around Okamura, Aa-chan, Aya, a woman who has been working for two years and has begun living on her own for a job opportunity. With Aa-chan's mother working overseas as a doctor, Aa-chan's father is now living alone with the family's longtime pet cat Mii-san. One night, Aa-chan returns from a long day at work, and as she rests on her bed, she reminiscences about the times the family had together. She remembers the sadness she felt when her mom went overseas, and the solace she felt when her father brought home Mii-san to give her comfort. Then, she receives a phone call...

Keitarou Gentouga is a college freshman who hates ghosts. Unluckily for him, he has a knack for attracting spirits. Two years ago, this connection had led to him receiving a spiritual injury on his right hand, with his friend getting caught in the crossfire. The event caused him to become a shut-in, leaving him with very poor social skills. Fortunately, Keitarou is slowly starting to mingle with society, thanks to the help of his childhood friend, Eiko Houzuki. As part of his rehabilitation, Keitarou takes on the part-time job of a private tutor, and his first pupil is none other than Eiko's cousin, Yayoi Houzuki. Besides being a child prodigy, there is another peculiarity regarding Yayoi—she has a spiritual constitution, just like Keitarou. However, in contrast to Keitarou, she yearns to encounter spirits, hoping to find the ghost that took her mother away. As Keitarou is dragged along by Yayoi and Eiko to haunted spots, his part-time job seems to be straying further and further away from its original purpose.

Spirits have always been attracted to Keitarou Gentouga due to his strong spiritual presence. A traumatic encounter with one had caused his right hand to be cursed, forcing him to wear a glove at all times. Now a college freshman, Keitarou is trying to live as normal a life as possible. With the encouragement of his childhood friend Eiko Houzuki, he becomes a private tutor. Since he is at the top of his intake class, his first client is the tutoring firm's most promising student, Yayoi Houzuki. To Keitarou's surprise, Yayoi is Eiko's cousin, and she possesses two pupils in each eye—allowing her to see into the spirit world and purposely seek vengeful spirits to exorcise. Ever since a car accident killed both her parents, Yayoi has been searching for the powerful spirit that kidnapped her mother's departed soul. Seeing that spirits are so attracted to Keitarou, she ropes him into helping her collect other evil spirits that will assist in her future fight. Although her quest is dangerous, Keitarou reluctantly decides to join her, even as each new spirit they meet has him questioning his resolve at every turn.

 In Tokyo, an impenetrable field known as “Hell’s Gate” appeared ten years ago. At the same time, psychics who wield paranormal powers at the cost of their conscience also emerged. Hei is one of the most powerful of these psychic agents, and along with his blind associate, Yin, works for one of the many rival agencies vying to unlock the mysteries o… more In Tokyo, an impenetrable field known as “Hell’s Gate” appeared ten years ago. At the same time, psychics who wield paranormal powers at the cost of their conscience also emerged. Hei is one of the most powerful of these psychic agents, and along with his blind associate, Yin, works for one of the many rival agencies vying to unlock the mysteries of Hell’s Gate.

Tells the story of what happened to Yin and Hei between the first and second series.

The story of what happened to Yin and Hei between the first and second series.

In Tokyo, an impenetrable field known as "Hell's Gate" appeared ten years ago. At the same time, psychics who wield paranormal powers at the cost of their conscience also emerged. Hei is one of the most powerful of these psychic agents, and along with his blind associate, Yin, works for one of the many rival agencies vying to unlock the mysteries of Hell's Gate.

Two years have passed since Hei and Yin escaped the Syndicate after the events of the first season. Making their way to Russia, Hei encounters a young girl named Suou Pavlichenko, whose family is gradually pulled into the war between contractors and various intelligence factions. Meanwhile, Kirihara Misaki has quit her position in Foreign Affairs to begin her own investigations into Hei, the Contractors and the Syndicate.

In the sequel, Hei and Yin are now on the run after betraying the Syndicate in the previous season. After leaving Japan, Hei encounters Suou Pavlichenko, a 13-year-old Eurasian girl who becomes embroiled in the war and politics of the various factions and Contractors vying for power. Meanwhile, Hell's Gate remains standing in Tokyo, after Hei's efforts to stop the Saturn Ring anti-Gate particle weapon from activating. Although Contractors are safe from the danger of having their existences erased, this does not prevent new and old Contractors from abusing their powers. As Misaki Kirihara and her team in the Public Security Bureau deal with the increasing Contractor cases, she also has to keep the Syndicate at bay, who has major positions in the Japanese police and intelligence bureaus around the world. The storyline setting primarily takes place in both Japan and Russia.

The Persona Century Corporation has purchased nearly every parcel of land on earth. Dissension is not tolerated within the corporation's borders and those who oppose Persona are dealt with swiftly. Of those few places not yet under Persona's control is the free town of Kabuki-cho, also known as "The Dark Side of Tokyo". Within the town, under the leadership of a woman named Mai, is a small resistance group called Messiah. Into this world steps a man who takes the sobriquet of Kabuki-cho: Darkside. Sealed up in another dimension eighteen years ago by Persona Century, Darkside now returns to aid Messiah using his unique mystic power of renewal.