"SSSS.Gridman" is a 12-episode anime series that reimagines the 1993 tokusatsu series "Gridman the Hyper Agent." The narrative centers on Yuta Hibiki, a high school student who loses his memories and begins experiencing strange visions of a giant robot named Gridman. Yuta discovers that he can merge with Gridman to combat kaiju—mysterious monsters that suddenly appear in the city of Tsutsujidai. Alongside his classmates Rikka Takarada and Utsumi Shou, Yuta investigates the origins of these kaiju and the peculiar nature of their seemingly idyllic town.

The kaiju attacks are orchestrated by Alexis Kerib, a malevolent entity from the digital world who manipulates a human accomplice, Akane Shinjo. Akane, a classmate of Yuta and Rikka, creates the kaiju as a form of escapism, using them to eliminate people and aspects of her life she finds dissatisfying. As Yuta and Gridman confront the kaiju, they uncover the truth about Tsutsujidai: the town is a fabricated reality within a computer simulation, and its inhabitants are digital constructs. Akane, unaware of her own role in this simulation, struggles with her growing detachment from reality and her desire for control.

The series explores themes of identity, reality, and the consequences of escapism. Yuta's journey to regain his memories and protect his friends intertwines with Gridman's mission to restore balance. Rikka serves as a grounding presence, offering emotional support and insight into Akane's deteriorating mental state. Utsumi, a tech-savvy enthusiast, aids in deciphering the mysteries of Gridman and the kaiju. The dynamic between the characters evolves as they confront the moral complexities of their situation, particularly in relation to Akane's actions and her eventual confrontation with the consequences of her choices.

The climax sees Yuta and Gridman facing off against Alexis Kerib in a final battle to save Tsutsujidai and its inhabitants. The resolution emphasizes the importance of confronting reality and the value of human connections, even within a simulated world. The series concludes with Yuta regaining his memories and bidding farewell to Gridman, while Akane begins to grapple with her role in the events that transpired. The ending leaves room for interpretation, suggesting a cyclical nature to the struggle between creation and destruction within the digital realm.