"Luminous Witches" is set in an alternate world where humanity faces an alien threat known as the Neuroi. The story revolves around a unique squadron of witches who, unlike traditional combat units, use their magical abilities to perform and inspire through music rather than direct warfare. This squadron, called the Luminous Witches, is part of a larger effort to boost morale and provide hope to a world besieged by conflict.

The protagonist, Aira Paylor, is a young witch from Britannia who dreams of becoming an idol. Despite her lack of combat prowess, Aira is recruited into the Luminous Witches due to her exceptional musical talent and her ability to connect with others through her performances. The squadron is composed of witches from various nations, each bringing their own cultural influences and musical styles to the group. Key members include Manaiarifa "Manai" Tupou, a cheerful and energetic witch from Oceania; Elly, a reserved and disciplined witch from Orussia; and Inori, a shy but talented witch from Fuso.

The narrative explores the challenges the Luminous Witches face as they strive to unite people through their music. Their performances are not only a form of entertainment but also a means of fostering unity and resilience in the face of the Neuroi threat. The series delves into the personal struggles and growth of each character, highlighting their individual journeys as they overcome insecurities, cultural differences, and the pressures of their roles.

As the story progresses, the Luminous Witches encounter various obstacles, including skepticism from traditional military units and the ever-present danger of the Neuroi. Despite these challenges, the squadron remains committed to their mission, using their music to inspire hope and bring people together. The series balances moments of lighthearted camaraderie with deeper themes of perseverance, unity, and the power of art to transcend adversity.

"Luminous Witches" is a spin-off of the "Strike Witches" franchise but distinguishes itself by focusing on the non-combatant aspects of the witches' roles. The series emphasizes the importance of morale and emotional support in times of crisis, offering a unique perspective on the ongoing conflict with the Neuroi. Through its diverse cast and emphasis on music, the series presents a heartfelt exploration of the ways in which individuals can contribute to a greater cause, even without direct involvement in battle.