Well Saitama was just doing his everyday routine like being a hero and getting bored cause of his one punch but one day an outer space alien like enemy came to City F all the class S hero where alerted of this attack but all of them failed to defeat the Enemy then the association finally call all the heroes even in Class C where saitama was in, all the heroes attack but all defeated except one and it's Saitama the Enemy where force to retreat cause of the incredible strength that was shown by Saitama but one of them accidentally press a world transporter and was aim to Saitamas direction, Saitama look curiously of what is the light that was forming a big ball of red electricity, he then get closer and all of a sudden it zap at Saitamas face that resulted a large impact, after that saitama wake up in an another world where the people there where using chakra and the worst of all he turned into a 12 year old kid!!, will saitama return in his world?
13 parts