Watch Chicago P.D. Season 4 Episode 18 Online. Best and Free Online streaming for Chicago P.D. TV Show. We picked the best sites to stream s04e18. Simply pick a site below and click "Watch Now!" button next to it. Some of the links may be broken, please upvote the working and good links so other users see those links for Chicago P.D. Season 4 Episode 18 s04e18 at the top of the list.