Watch Once Upon a Time Season 6 Episode 18 Online. Best and Free Online streaming for Once Upon a Time TV Show. We picked the best sites to stream s06e18. 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 Once Upon a Time Season 6 Episode 18 s06e18 at the top of the list.