Season 4

Aku sends a Ninja to destroy Jack who is busily helping a port town in distress.

Jack enters a village to discover that he is their Chosen One meant to embody the Robo-Samurai and destroy the Mondo-bot that has come to destroy them.

Jack is approached by a cool Samurai-punk who wants to battle with Jack in order to prove that he is the best.

When ancient gods try to destroy a powerful evil, they send one piece of the beast hurtling through space. This piece lands on earth, spreading its evil through the land. When it encroaches on an Emperor's empire, he takes it upon himself to destroy the evil, but ends up unleashing the evil that is Aku.

Jack has lost all memory of who he is and it's up to the Scotsman to put the pieces of the puzzle together to save the samurai.

When Aku catches a cold and sneezes on Jack, Jack becomes infected with Aku’s badness which begins to take over his entire body.

When Aku raises the bounty on Jack, the best bounty hunters in the world gather to capture him.

Jack helps save a Prince and Princess whose ship has been shot down to Earth by Aku.

Tired of all the bounty hunters and robots failing, Aku fights Jack, mano y mano.

As Jack goes through fall, winter, spring and summer, he must battle the perils that each season brings.

Aku forces an old, ace robot assassin out of retirement to eliminate the ultimate mark - Jack.

Young Jack is brought to Africa for part of his training, but when his tribe is abducted, he must learn how to use their unique sword-like weapon – and fast!

Jack finds a baby and the two travel together as Jack tries to return the boy to his mother.