"Augmented Reality Girls Trinary" is set in a near-future world where augmented reality (AR) technology has become deeply integrated into daily life. The story revolves around a group of young women who are part of a secret government project called "Trinary," which aims to combat cyber-terrorism and other digital threats using advanced AR systems. These systems allow the girls to interact with and manipulate digital environments in real-time, blending the physical and virtual worlds seamlessly.

The protagonist, Yūka, is a high school student recruited into the Trinary project due to her exceptional ability to adapt to AR interfaces. Alongside her teammates, the stoic and analytical Rina and the cheerful yet unpredictable Saki, Yūka is tasked with neutralizing dangerous AR-based anomalies and rogue programs that threaten the stability of society. Each girl possesses unique skills that complement the team dynamic, with Yūka serving as the emotional anchor, Rina as the strategist, and Saki as the wildcard.

The narrative explores the challenges the team faces as they balance their personal lives with their responsibilities as Trinary operatives. Yūka struggles with the moral implications of their missions, particularly when confronting human adversaries who exploit AR technology for malicious purposes. Rina’s past as a former hacker adds layers of complexity to her character, as she grapples with guilt and redemption. Saki’s unpredictable nature often leads to both comedic and tense moments, but her loyalty to the team remains unwavering.

As the series progresses, the girls uncover a larger conspiracy involving the origins of the Trinary project and its connection to a shadowy organization manipulating AR technology for global control. The stakes escalate as the team confronts increasingly sophisticated threats, culminating in a climactic battle that tests their resolve and unity. Themes of trust, identity, and the ethical use of technology are woven throughout the story, highlighting the potential dangers and benefits of a world where reality and virtuality are indistinguishable.