"Magical Girl Site" is a dark fantasy anime that explores themes of bullying, trauma, and the consequences of wielding supernatural power. The protagonist, Aya Asagiri, is a middle school student who endures relentless bullying at school and abuse at home. Her life takes a drastic turn when she encounters a mysterious website called "Magical Girl Site," which grants her magical powers through a magical gun. However, the gift comes with a grim condition: she must use her powers to fight other magical girls or face dire consequences.

Aya is joined by Tsuyuno Yatsumura, another magical girl who becomes her ally. Tsuyuno is more experienced and initially appears cold and distant, but she gradually forms a bond with Aya as they navigate the dangerous world of magical girls. The two discover that the website is part of a larger, sinister system orchestrated by a figure known as "Admin," who manipulates the girls into violent confrontations. The magical girls are given limited time to live, as their powers accelerate their mortality, adding urgency to their struggles.

As the story progresses, Aya and Tsuyuno encounter other magical girls, each with their own tragic backstories and motivations. These characters include Sarina Shizukume, a girl who uses her powers to exact revenge on those who wronged her, and Nijimi Anazawa, a cheerful yet enigmatic girl with a hidden agenda. The series delves into the psychological toll of their circumstances, as the girls grapple with their newfound powers, the moral dilemmas of using them, and the inevitability of their shortened lifespans.

The narrative builds toward a confrontation with Admin, who is revealed to be a former magical girl seeking to perpetuate the cycle of suffering. The series culminates in a climactic battle where Aya and her allies must decide whether to continue the cycle of violence or find a way to break free from it. "Magical Girl Site" combines elements of psychological drama, action, and horror, presenting a bleak yet compelling exploration of its characters' struggles and the dark world they inhabit.