Rikka Takanashi, a high school freshman, suffers from "chuunibyou," a condition where individuals, often adolescents, adopt delusional behaviors and believe they possess supernatural powers or secret identities. Rikka calls herself the "Wicked Eye" and wears an eyepatch, claiming it seals her immense power. Yuuta Togashi, a classmate, once struggled with similar delusions, calling himself the "Dark Flame Master," but has since outgrown this phase and seeks a normal high school life. Despite his efforts to distance himself from his past, Yuuta becomes entangled with Rikka when she discovers his old journal detailing his chuunibyou fantasies.

The series explores their evolving relationship as Yuuta reluctantly becomes Rikka's companion in her imaginative escapades. Rikka's delusions often lead to comedic and awkward situations, blending slice-of-life elements with lighthearted fantasy. Supporting characters include Shinka Nibutani, a former chuunibyou sufferer who now tries to maintain a mature facade, and Kumin Tsuyuri, a laid-back upperclassman who enjoys napping and occasionally indulges in Rikka's antics. Sanae Dekomori, Rikka's self-proclaimed "vassal," adds to the chaos with her own chuunibyou persona, "Mori Summer."

As the story progresses, deeper layers of Rikka's behavior are revealed, tied to her family dynamics and unresolved grief over her father's death. Her chuunibyou acts serve as a coping mechanism, shielding her from emotional pain. Yuuta, while initially frustrated by Rikka's antics, gradually develops feelings for her and becomes determined to support her, even if it means embracing parts of his past he had tried to leave behind. The narrative balances humor and heartfelt moments, culminating in a resolution that addresses Rikka's emotional struggles and the growing bond between her and Yuuta.

The series also includes a second season, "Chuunibyou demo Koi ga Shitai! Ren," which further explores the challenges of their relationship as external pressures and misunderstandings arise. Themes of self-acceptance, personal growth, and the complexities of adolescence are central to the story, presented through a mix of comedic and poignant moments. The dynamic between the characters, particularly Yuuta and Rikka, drives the narrative, offering a blend of fantasy and realism that resonates with themes of identity and emotional healing.