"Gekijо̄-ban Nintama Rantaro Dokutake Ninja-tai Saikyо̄ no Gunshi" is a feature-length anime film based on the popular "Nintama Rantaro" series, which blends comedy, action, and ninja-themed adventures. The story centers on Rantaro, a young and spirited ninja-in-training at the Ninjutsu Academy, alongside his classmates Kirimaru and Shinbei. The trio, despite their comedic misadventures and lack of skill compared to their peers, often find themselves at the heart of significant events.

The narrative unfolds when the Ninjutsu Academy faces a grave threat from Dokutake Ninja-tai, a formidable group of rogue ninjas led by the cunning strategist Gunshi. Dokutake Ninja-tai seeks to overthrow the academy and seize its secrets, posing a direct challenge to the students and faculty. Rantaro, Kirimaru, and Shinbei, driven by their determination to protect their school, embark on a mission to thwart the enemy's plans. Along the way, they encounter various obstacles, including traps, rival ninjas, and their own insecurities, but their camaraderie and resourcefulness help them navigate these challenges.

The film emphasizes themes of teamwork, perseverance, and the importance of believing in oneself, even in the face of overwhelming odds. The characters' growth is highlighted as they learn to harness their unique strengths and work together to outsmart their adversaries. The story balances humor with moments of tension, staying true to the lighthearted yet adventurous tone of the series. By the climax, the trio's efforts culminate in a decisive confrontation with Dokutake Ninja-tai, showcasing their development as ninjas and their unwavering commitment to their academy.