When Bubba and Squirt travel through the mysterious vortex on a quest to save their father, they end up in Athens, Greece where they meet an old woman known as the Oracle of Delphi. Her intriguing riddles set them on a path that leads to the Netherworld, a place where danger lurks around every corner.

With the help of their new friends and some unlikely allies, they must defeat the monster that holds their father captive. Will they succeed or be trapped forever in the labyrinth of the Netherworld?