Premise

Sir Sigmoid's Arcadia is based around a traveling carnival which appears in the Ectosphere (the realm of the dead). The carnival is run by Sir Sigmoid, an evil demon who eats the souls of children.

Ectokid and Saint Sinner

Ectokid is drawn to the carnival when he sees a signpost advertising it. Next to the signpost is a worm in a top hat, named Tequila. The worm jumps into Ectokid's ear and takes control of him, luring him to the carnival. When he gets there, he meets a young man named Phillip Fetter, who appears to be just a normal dead teen, enjoying the games of Sir Sigmoid's Arcadia. What he doesn't know is that this is really the soul of a man better known as Saint Sinner, who isn't really a teenager at all. The carnival appears to have lulled him back to a comforting, childhood state.

The two boys meet, and instantly get along, finding that they have an awful lot in common. Both have the same taste in music, and both are not quite dead, existing in a grey area between life and death.

Escape From Arcadia

Though he is a formidable opponent, it is not Sir Sigmoid who presents Ectokid with his greatest challenge, when it comes to escaping from Arcadia. His biggest challenge is convincing Saint Sinner to leave. He is reluctant to go back to the real world, where he will no longer be a teenager. Also, he knows that going back to his body means having to fight for control of it all over again - in the Ectosphere, he is not possessed, and can enjoy free will.