Free movie sites operate in a shady area of the law. Strictly speaking, unless the website has officially licensed the streaming of the movie to the public, then it is violating the copyright of the movie or series you are watching. But because these sites usually operate from lax jurisdictions, they can typically get around the laws until law enforcement agencies take down their domains. If you want to be 100% safe, used a paid service for streaming movies online like Netflix or Amazon Prime.