在这部暗杀教室动画片中,故事发生在椚丘中学三年E班，表面上，这是一个普通的班级，然而实际上，这里聚集着的均是技艺高超冷酷无情的杀手。每一年，他们通过特殊渠道接收着来自世界各地的暗杀任务，替各国首脑“排忧解难”，而这一次，他们有了一个统一的目标——刺杀班主任杀老师（福山润 配音）。
杀老师是一个神奇的存在，它的外表并非人类，却有着及其敏感的神经和及其迅速的反应力，没有人知道它从哪里来，也没有人知道，它为何会变成三年E班的班主任。因为想要毁灭地球，杀老师成为了暗杀名单上的高价悬赏人物，而作为三年E班的学生，只要成功消灭杀老师，即可毕业。就这样，围绕着这位神秘的老师，充满了危险的日常就此展开。
The Earth is threatened by a powerful creature who destroyed 70% of the Moon with its power, rendering into the shape of a crescent moon forever. The creature claims that within a year, Earth will also be destroyed by him, but he offers mankind a chance to avert this fate. In class 3-E at Kunugigaoka Junior High School, he starts working as a homeroom teacher where he teaches his students not only regular subjects, but the ways of assassination. The Japanese government promises a reward of ¥10 billion (i.e. 100 million USD) to whoever among the students succeeds to kill their teacher, whom they have named "Korosensei" . However, this has proven to be an almost impossible task, as he has several inhuman abilities at his disposal, including the capacity of moving at Mach 20.
一种翻译，不一定对。从前有个触手怪……然后呢？。看到第九集，总结一下感想。撒哟啦啦 可乐三三（再见杀老师）。复盘《暗杀教室》（上）。极限与矛盾——《暗杀教室》的过度解读。我很丑可是我很温柔。不太喜欢看周刊少年，这里只有恶魔奶爸和齐木楠雄过得去。。高三结束的日子。你是我们最好的老师。
