"Yumemiru Danshi wa Genjitsushugisha" centers on Wataru Sajou, a high school student who once harbored grand dreams of becoming a hero in a fantasy world, inspired by his love for light novels and games. Over time, however, he matures into a pragmatic realist, distancing himself from his earlier fantasies. Despite this shift, Wataru retains a deep understanding of otaku culture and a sharp wit, often using his knowledge to navigate social situations.

The narrative explores Wataru's interactions with his classmates, particularly Aika Natsukawa, a popular and academically gifted girl who initially appears to be the archetypal "perfect" student. Aika, however, harbors her own insecurities and struggles, which gradually come to light as her relationship with Wataru develops. Their dynamic is marked by playful banter and mutual growth, as Wataru's grounded perspective helps Aika confront her vulnerabilities, while her presence challenges Wataru to reconsider his dismissive attitude toward dreams and idealism.

The story also delves into the lives of other characters, such as Kei Ashida, Wataru's childhood friend and a fellow realist, and Sana Shinonome, a shy and reserved classmate who shares Wataru's interest in otaku culture. These relationships add depth to the narrative, highlighting themes of self-discovery, the balance between dreams and reality, and the importance of human connections.

The plot unfolds through a series of episodic yet interconnected events, blending humor, introspection, and lighthearted romance. Wataru's journey is one of reconciling his past idealism with his present pragmatism, ultimately finding a middle ground where he can appreciate the value of dreams without losing sight of reality. The series balances its comedic moments with thoughtful exploration of its characters' inner lives, creating a narrative that is both entertaining and reflective.