"Mask of Zeguy" is a two-episode OVA series that blends historical fantasy, action, and supernatural elements. The story is set in modern-day Tokyo but quickly shifts to a mystical world intertwined with historical and mythological themes. The narrative centers on Miki, a high school girl who becomes entangled in a quest involving ancient artifacts and a battle between good and evil. Miki discovers a mysterious mask, the titular "Mask of Zeguy," which grants her access to a hidden realm and connects her to a centuries-old conflict.

The mask is one of three powerful artifacts tied to the legendary Queen Himiko, a historical figure from ancient Japan. These artifacts are sought by various factions, including the villainous Shikima, who aims to use their power for malevolent purposes. Miki is joined by two companions: Shamon, a warrior from the past, and Remei, a skilled fighter who aids her in navigating the dangers of this mystical world. Together, they embark on a journey to prevent Shikima from obtaining the artifacts and unleashing chaos.

The plot unfolds through a series of battles, encounters with supernatural beings, and explorations of the mystical realm. The story incorporates elements of Japanese mythology and history, particularly the legend of Queen Himiko, to create a unique backdrop for the action. The characters face moral dilemmas and personal challenges as they confront the forces of evil, with Miki’s growth as a protagonist serving as a central focus. The series concludes with a climactic confrontation that resolves the immediate conflict while leaving room for further exploration of its rich mythological setting.