In ancient Japan, the shape shifting wizard known as Aku resurfaces and attacks the nation. When the emperor is captured, his son is sent to train throughout the world in many forms of discipline and combat. As an adult, he reunites with his mother, who gives him the sacred sword capable of defeating Aku. When the samurai returns home to face the wizard, he is sent through time into the distant future, where Aku still rules over a world filled with high technology, aliens, and other oddities that the samurai doesn't understand. Taking on the name Jack, the samurai makes a name for himself as he struggles to free the future from Aku's grasp, and one day return to his own time to stop Aku before this future comes to pass.