The castle is bustling as King Henry makes his way home from Paris on tonight's episode of 'Reign.' Olivia is busy trying to get back together with Francis, Mary warns Kenna that her new position as Royal Mistress might be risky, and Queen Catherine just can’t stop meddling in her son’s love life. She’s still anti-Mary and pro-Olivia, and she manipulates Olivia into thinking that a marriage with Francis will -- among other benefits -- erase Olivia’s trampy reputation. Oh, what a mother-in-law Catherine will be.

The queen might not need to work so hard, though. Francis is still fuming because he saw Mary kissing Sebastian, and he gives her the cold shoulder. Mary discusses the kiss with Sebastian, and the two of them are still clueless that Francis knows about it.

Then King Henry returns, and Kenna is starry-eyed when he steps out of his carriage—that is, until she realizes she isn’t the only mistress in town. Yes, that’s right… Diane (Sebastian’s mom) is back, and Kenna is miffed.

Adding to this royal drama is the pagan problem. They’re everywhere: surrounding the palace, in the woods and maybe even in Mary’s room. This is suspected when a freaky necklace shows up in her bed, and especially when she wakes to find blood dripping on her hand and a stag’s head strung up over her head.

Turns out, this is Sebastian’s fault. He interrupted a pagan sacrifice in the woods a while ago, and the only way to make up for it is to perform a human sacrifice. If he doesn’t, the pagans will come after someone he cares about. And who does Sebastian care about most these days? Mary, of course.

Sebastian struggles to plan his next move while Kenna deals with all the hardships of being King Henry’s mistress. Her fellow ladies-in-waiting aren’t exactly impressed with her new status, and there is just way too much Diane in the king’s quarters. She decorated the place, and even her initials are emblazoned into the tiles. Kenna complains to King Henry, who ends up ripping up the floor but is definitely not kicking Diane to the curb. He hooks up with her in her new cottage and does some smack-talking about Kenna.

Meanwhile, Sebastian finds a thief to sacrifice and strings him up by his ankles in the woods. But Sebastian is too honorable to actually go through with this, so he uses the thief as a decoy and sacrifices a pagan instead. On the way back to the palace, the thief lets it slip that he knows Sebastian is the king’s illegitimate son, and Sebastian is therefore forced to push him off a cliff.

Back at the palace, a guard and a maid are accused of planting the stag’s head in Mary’s room, and Sebastian tells Mary and Francis that he took care of that pesky human sacrifice.

Francis grabs this opportunity to reveal that he saw Sebastian and Mary locking lips and, by the way, he thinks Mary is such a troublemaker. Ever since she rolled into the castle, things have been going downhill... and that has to change. He proposes that he and Mary have an open engagement because they might never get married, anyway -- so she’s free to see other people. But there’s a catch, of course. Mary can have any man she wants… excluding Sebastian. And if this agreement is broken? Well, Francis just might have to kill Sebastian, now won't he?

With that settled, Francis runs straight to Olivia, Sebastian tells Diane that Francis threatened his life, and Mary and the gals listen to the screams of the guard and the maid, who have been turned into a human bonfire on the palace grounds.