The only reason for being the strongest… is effort!! Ichitaro, a high school boy, has a personality that makes him immerse himself in one thing. One day, his entire class is reincarnated into another world as heroes. The rank assigned to him as a hero at the destination is "Worst." As an unnecessary existence, Ichitaro is locked in a prison where time has stopped. What he did there was 100 million years of training. By the time he left the prison, he had mastered every kind of swordsmanship, becoming the strongest hero!!