The first episode of "Majo to Yajuu" introduces the world of witches and their influence on society. The Origin Witches, the pinnacle of sorcery, have passed down their magical powers and knowledge to the current generation of witches, who sometimes help and sometimes curse humans.

The episode follows Guideau and Ashaf as they search for a specific witch in the city of Blazing Red. They encounter a baker, Marie, who leads them to a renowned witch, Lady Witch Ione, who is revered as the city's heroine.

A confrontation ensues when Guideau, driven by her own motives, accuses Ione of being the witch they are seeking. Ione denies knowing Guideau but is accused by her of being a liar. The police intervene, but Guideau passionately speaks out against trusting witches and warns of the inherent danger they pose.

Ashaf and Guideau are forced to leave the scene, but not before Ashaf voices his suspicions about the true nature of witches and their curses. Ashaf reveals to Guideau the history of the city, which involves a curse that transformed it into a land of hellfire. This curse was supposedly sealed in a castle now inhabited by the Witch Mistress Ione.

During a party at the castle celebrating an unknown anniversary, Ashaf and Guideau encounter Ione and Marie again. Ashaf questions the truth behind the city's history and the nature of the sealed curse, hinting that witches always bring secrets and dangers. Marie defends Ione by recounting her contributions to the city and how she ended the discrimination against witches.

However, the episode takes a dark turn when Ione reveals her true intentions. She admits to plotting revenge for years, exploiting her position and influence in the city. Ione reveals that she is the granddaughter of the original "evil witch," who was wrongfully accused and executed. Her goal is to unleash the hellfire slumbering within the city to avenge the injustice done to her family.

A battle breaks out between Ione and Guideau. Ashaf, a self-proclaimed first-class magician, does not participate, acknowledging Guideau's unique abilities as the greatest natural enemy of witches.

The episode ends with Guideau frustrated as her quest for revenge against a specific witch who cursed her leads to another dead end. Ashaf and Guideau, members of the Order of Magical Resonance, leave the city and continue their mission to restore order among witches and resolve magical issues.