Best ways to download copyrighted show on youtube

Hey guys! There's this old show i've been looking for that i haven't been able to find anywhere. I want to download them because i don't know how long youtube will keep it. But, its copyrighted so it doesn't seem to work for any of the youtube downloaders i've tried. do you guys know a youtube video downloader that lets me download video in 480 p with just 1 click? Let me know if you guys know any good apps or websites.

EDIT: The show i want to download is a copyrighted ( possibly drm protected ) show uploaded by youtube movies & tv channel.