Shoutarou Hidari, a hard-boiled private investigator from the Narumi Detective Agency, lives for the sake of protecting the peace in the city of Fuuto alongside his inquisitive partner, Philip. One fine night, Shoutarou encounters a mysterious woman named Tokime, who is soon linked to several cases of homicide and theft. Shoutarou's investigation leads him to people using "Gaia Memories"—memory units similar to thumb drives holding vast amounts of data—to turn into formidable beasts called "Dopants." While the majority of Gaia users were put down by the detective team in the past, a number of them still remain, posing a great threat to public safety. Once more, Shoutarou and Philip, Gaia users on the side of justice, must fight as Kamen Rider W—the renowned hero safeguarding Fuuto—to eradicate the nest of villainous Dopants, all while uncovering Tokime's true identity and confronting the long-forgotten past.

Beautiful sisters Ai, Mai, Mii, their android maid Mea and slippery pet ferret Unagi make an amazing journey together through time and space without ever leaving their beloved mansion behind! Following the clues of the strange dandelion-like "Popotan," the girls are theoretically seeking the person who has the answers to their most personal questions, but they seem to have more than enough time to take side trips, meet new friends, visit hot springs and occasionally operate the X-mas shop they keep in the house along the way! Yet, the girls' ultimate destiny holds more than a few surprises of its own, and not every moment is filled with hilarity, as moving through time means having to leave friends behind as well.

The first short story focuses on Favaro and Kaiser between the events of the first and second series as they visit Favaro's home village. The second short story shows Kaiser as a knight commander sparring with Jeanne, and sharing the reasons they remained as Orleans Knights in the aftermath of the final battle against Bahamut.

Thousands of years ago, the ancient dragon Bahamut wrought havoc upon the land of Mistarcia, a world where both gods and demons live amongst mankind. Working together to prevent the world's destruction, the rival deities barely managed to seal Bahamut, agreeing to split the key between them so that the dragon would remain eternally imprisoned. With the world safe from the destruction of Bahamut, it is business as usual for bounty hunters like Favaro Leone. Living a laid-back, self-serving lifestyle, the amoral Favaro goes about his work while on the run from fellow bounty hunter Kaisar Lidfard, a righteous man who swears vengeance upon Favaro. However, Favaro's carefree life is thrown into chaos when he meets Amira, a mysterious woman who holds half of the key to the world's fragile peace. Shingeki no Bahamut: Genesis tells the story of a group of unlikely heroes who find themselves caught in the middle of an epic clash between gods and demons, forced to carve their own path in the face of the imminent storm.