"Gridman Universe" is a continuation of the "SSSS.Gridman" series, expanding on the narrative established in its predecessor. The story is set in a world where the protagonist, Yuta Hibiki, continues to navigate his dual life as a high school student and the human host of Gridman, a hyper-agent tasked with protecting the city from kaiju threats. The series delves deeper into the dynamics between Yuta, his friends Rikka Takarada and Utsumi Sho, and the enigmatic Akane Shinjo, whose connection to the digital world remains a central mystery.

The plot revolves around the emergence of new kaiju threats, which are revealed to be manifestations of deeper conflicts within the digital realm. As Yuta and Gridman confront these adversaries, they uncover layers of the digital world's structure, including the existence of other hyper-agents and the true nature of Akane's role in shaping this reality. The narrative explores themes of identity, reality, and the consequences of human emotions on the digital landscape, as the characters grapple with their own insecurities and the moral implications of their actions.

Key characters include Yuta, whose growth as a person and as Gridman's partner is central to the story. Rikka and Utsumi provide emotional and tactical support, while Akane's complex motivations and her past actions continue to influence the unfolding events. The series introduces new characters, such as additional hyper-agents and digital entities, who challenge the protagonists and add depth to the world-building.

The storyline is structured around episodic battles with kaiju, interspersed with character-driven moments that reveal the psychological and emotional stakes. The series builds toward a climactic confrontation that ties together the personal struggles of the characters with the larger conflict in the digital world. Through its blend of action, mystery, and introspection, "Gridman Universe" offers a compelling exploration of its central themes while advancing the narrative established in the "SSSS.Gridman" series.