"Petit Eva - Evangelion@School" is a comedic spin-off of the iconic "Neon Genesis Evangelion" series, reimagining its characters in a lighthearted school setting. The narrative unfolds at Tokyo-3 First Municipal Junior High School, where the main characters are students navigating everyday school life. Shinji Ikari, Asuka Langley Soryu, and Rei Ayanami are classmates, with Misato Katsuragi serving as their homeroom teacher. Gendo Ikari, Shinji's father, is the school principal, and Ritsuko Akagi works as the school nurse.

The series parodies the original "Evangelion" universe by incorporating its characters and themes into mundane, humorous scenarios. For instance, the Evangelion units are reimagined as quirky school mascots, and the Angels are portrayed as mischievous entities causing minor disruptions. The plot revolves around the students' interactions, often highlighting their exaggerated personalities and relationships. Shinji remains timid and reluctant, Asuka is brash and competitive, and Rei is stoic and enigmatic, but these traits are played for comedic effect rather than dramatic tension.

Episodes are short and episodic, focusing on slice-of-life situations such as school festivals, exams, and club activities, all infused with absurd humor and references to the original series. The tone is consistently light and satirical, contrasting sharply with the dark, philosophical themes of "Neon Genesis Evangelion." The series also includes cameos from other "Evangelion" characters, such as Kaworu Nagisa and Pen Pen, who are integrated into the school setting in amusing ways.

Overall, "Petit Eva - Evangelion@School" offers a playful reinterpretation of the "Evangelion" franchise, emphasizing humor and parody over its source material's complex narrative and emotional depth. The characters retain their core identities but are placed in a context that exaggerates their quirks for comedic purposes, creating a whimsical and accessible take on the original series.