今回"忍たま"たちが挑むのは、手にした者が天下を制するといわれている幻の妖刀・極楽丸の奪還。しかし、この刀をめぐって、ドクタケ城の面々をはじめ、さまざまな忍者たちも暗躍する。天下を狙う黒幕は誰だ?果たして"忍たま"たちは、この大乱戦をくぐりぬけ、任務を遂行することができるのか?
At a time when nations are warring, a sword with mysterious power called "Heaven's Sword" is stolen. The sword gives the bearer the power to conquer the world! Rantaro attends the Ninja Academy where he hopes to become an elite ninja. He and his classmates are assigned to retrieve the stolen sword, their first real ninja mission! As an incentive, it's proposed that the kids will have no schoolwork during the winter holidays if they succeed in the mission AND finish their summer homework in time! Rantaro and the classmates help each other and manage to retrieve the sword but fail to complete their homework. To the disappointed kids the teachers tell that all their homework assignments were included in the sword mission! Hooray! The ninja kids scream with joy!
1993年にスタートしたテレビアニメは、2013年で20周年!子供たちを中心に、幅広い世代によって長きにわたって愛され、「忍たま乱太郎」としてアニメ化、ミュージカル化などもされている大人気漫画「落第忍者乱太郎」。その実写映画が、大胆にスケールアップして登場!!
The live action feature film version of the popular manga that's been going for 27 years and sold 8.7 million copies. It's summer vacation! Rantaro and his goofy friends at the Ninja Academy must retrieve a stolen magic sword against great odds...so that they won't have to do extra schoolwork!