A novelist receives a letter from a female university student named Kubo about strange sounds that emanate from a room in her apartment. They begin to investigate incidents involving former residents, and eventually discover the shocking truths lurking inside the building.
Nagisa is 17 years old and attends second grade in high school. He is apart from his parents and lives alone in the seaside town of Fujisawa in Kanagawa. He is passionate about surfing and works at a bathhouse in a hostel on the island Enoshima linked to Fujisawa. Shun is the same age as Nagisa and visits Fujisawa for spring break. They meet and develop a relationship more than friendship. However, the surfing equipment store owner's daughter, Chika, has been secretly in love with Nagisa.
Five characters who "should not be in this world" have appeared before Emu. These characters are Kamen Riders who have either died or disappeared. The mystery behind their revival is linked both to someone manipulating strings behind the scenes and the "ultimate superhero team" Kamen Sentai Gorider.
Takeshi Hongo is a promising young man with a passion for motorcycle racing. However, his dreams are suddenly ruined when he gets kidnapped by Shocker, the evil secret organization planning to dominate the world. After being remodeled into a cyborg, Takeshi escapes and swears to protect the world from the inhuman monsters.
