We got an entire episode of Catherine helping Mary. This might go down as my favorite episode of this season. Catherine is really the the only mother figure that Mary has or possibly ever has (since her actual mother was in another country).
At this point, Mary is no longer Catherine's daughter-in-law, and Catherine isn't gaining anything from helping Mary to the extent that she does, but she does it anyway. You can tell that she's doing it and offering advice because she wants Mary to be happy, and I want to cherish that we got these moments between them before the show ends.
Mary confides in Catherine that she's pregnant with the child that she believes is the child of the prophecy, and at the risk of spoilers (though the show will never get there), she's not wrong that the kid will be important (though the kid was actually born eleven months after her marriage to Darnley).
Rizzio is also an actual person from history, but the way Reign has chosen to portray Rizzio as gay when rumors persisted at the time that he and Mary were having an affair is very interesting. (The actual Rizzio was accused of being the real father of Mary's child instead of Darnley.)
I love Rizzio on the show. He seemed like a cool guy when he was first introduced, but this episode cements it. He's one of those rare characters where you can tell he's a good person who doesn't have any ulterior motives. His presence is a breath of fresh air, and Mary needs more trustworthy friends in addition to Greer.
This episode was heartbreaking when it came to Emily Knox. It was inevitable that John Knox would discover the truth at some point, but that doesn't make watching it any less sad. And then Emily had to see James with Greer on top of that. I want her to have a happy ending, though I have no idea what that would look like. Hopefully we get some sort of hint that her life is heading in a positive direction before the show ends.
Catherine confronting Lady Lennox is the confirmation I didn't need that the two women are extremely similar yet also very different.
Another part of the episode that I enjoyed, though I don't have much to say about it, was getting to see Marteen with Rose. That was cute. (I wonder if Rose will still have the earrings next time we see her.)
The actual wedding of Mary and Darnley is as upsetting as you would imagine it being.
It did take me a bit to figure out what was going on with the people talking down English flags and putting up Scottish ones since I wouldn't have thought that changing allegiance was that quick or easy, but I suppose it works well enough symbolically.
Elizabeth and Gideon kissing wasn't a surprise, but I do wonder how that will develop over the rest of the season.