"To Protect and Serve" is an unreleased 5th episode of the Tales from Radiator Springs series. It was meant to air in 2015, but as of 2020, it has yet to surface.
The short was first announced at D23 Expo 2013 alongside the aired Radiator Springs 500 1/2 short. In March 2014, it was announced that a short was due to release in 2015. In October of the same year, it was discovered that the short was called To Protect and Serve.
But 2015 came and went, and although die-casts for both the new characters (pictured above) and the pre-existing characters were made, along with a children’s book version of the short, the short has never aired. Pixar has yet to explain why the short hasn’t been released yet.
No video of the short has ever been shown to the public. However, the book does contain images from the short. It has been speculated that the story in the book, as simple as it is, could be the same as the one in the short. Since then, no other shorts have been announced after To Protect and Serve, and it is likely the series has ended or been cancelled.