Samurai Jack is a samurai who lived in Medieval Japan until the evil demon Aku started terrorizing his village. Jack trained with the best fighters in the world in every single form of combat possible, and was given a magic sword that can destroy any evil being. However, when he confronted Aku, Aku opened a time portal and sent him forwards in time to the future, where Aku rules the Earth. Now stranded, he took the name "Jack" and travels around the future world looking for a way to back to his native time period and defeat Aku in the past.
Eventually, Jack manages to return to his time period and defeat Aku once and for all.