Plot: An entrepreneurial single mom who works with Santa Claus to reply to children's letters, complete with the North Pole postmark; an 83-year-old Ironman triathlon competitor from Malibu, California, and his millennial-aged business partner from Sandy, Utah, who invented a more functional winter glove; and two men from Glendale Heights, Illinois, who aim to make gift-giving more personalized with their product. Also, a "Shark Profile" on billionaire Mark Cuban