Shortly after the Day of the Departed, Master Wu awaits his old enemy Acronix to complete a battle they began 40 years ago. But Wu never should have faced such a powerful foe alone. Acronix hits Wu with the Time Punch, which causes him to start rapidly aging! Acronix escapes and reunites with his twin brother Krux, who has been living the past 40 years in disguise as the lovable Dr. Sander Saunders. During this time, Krux has been breeding a new slithering enemy: the Vermillion Warriors.