I have a feeling this is more for the people who want a gentle reminder of what has already happened, and is not really geared toward bringing new viewers in. HBO has released a five-minute video recapping the first six seasons of Game of Thrones.
For a show like maybe Arrow or maybe The Blacklist you could put together a multi-season recap that might be able to prepare new viewers for jumping in on the latest season. But there is no way you could summarize six seasons of George R. R. Martin's epic series in 50 minutes, let alone five. There are too many different names to cover, lands and lore to explain, and descriptions of how everything is all connected. Heck, just trying to recap the exploits of Tyrion Lannister alone would take over an hour.
For those of you ready for the season seven debut this Sunday at 9 p.m. ET on HBO, then take the five minutes and get all of the stories freshly back into your memory. If you are brand new to the series…go back to the beginning and watch them in order. Bring a notepad and a highlighter so you can take notes. Pause if need be to get names down. If you have access to a whiteboard, that might help. And for the love of God, do not get attached to any characters…none of them. It just leads to heartbreak.