The Killing Season is an immersive series that follows documentarians Joshua Zeman and Rachel Mills as they investigate one of the most bizarre unsolved serial killer cases of our time.The Killing Season is an immersive series that follows documentarians Joshua Zeman and Rachel Mills as they investigate one of the most bizarre unsolved serial killer cases of our time.The Killing Season is an immersive series that follows documentarians Joshua Zeman and Rachel Mills as they investigate one of the most bizarre unsolved serial killer cases of our time.