After 50 long years of battling Aku, Samurai Jack has started to slip into madness and finds that his psyche has now become his own worst enemy.
Jack's will to survive is pushed to its absolute limits after a deadly, unseen foe launches a relentless surprise attack.
A gravely injured Samurai Jack chooses to create his own fate by going up against the deadliest foes he's ever faced, Assassins from the Cult of Aku.
Samurai Jack must work with a deadly assassin bent on his destruction in order to escape the strange, otherworldly insides of a gargantuan creature that has swallowed them whole.
Ashi's search for Samurai Jack helps her to see his affect on the world after encountering numerous people and places where his heroics have changed things for the better.
Jack and Ashi must overcome a series of dangerous physical and spiritual tests in order to recover Jack's long lost sword.
Samurai Jack's worst fear is realized when he faces off against Aku, and the demon makes a shocking discovery about Ashi that puts her in grave danger.