Netflix content is all DRM protected. Try reading up on Widevine.
https://en.wikipedia.org/wiki/WidevineWhile it is fairly secure, it's not infallible. Netflix content is regularly ripped and released online. The techniques to do it are usually kept fairly secret to keep things from being patched. You'd have better luck downloading a version of the file that someone else has already ripped and released DRM free.
Are you able to share the file name that you're looking for?
As for the legal and moral implications of downloading a DRM free version of a show that you're paying for with your subscription, I'll leave that up to you.