“When Francis returns he wants to show Mary that his relationship with her supersedes all other relationships in his life,” star Toby Regbo tells Zap2it. “There is that factor of him having a new family he wants to care for, but he wants to make sure that Mary knows that she is more important than this thing he has with Lola, this civil relationship that he has to maintain with the mother of his child. He wants to say ‘I love you’ to her, but when he gets back to the castle Mary has done a thing that has made it really difficult for me to sort of crawl right back." 

Oh, right: She sentenced Lord Narcisse’s son to death in the dungeons with plague victims. Francis is not going to like that. 

"We’re immediately thrown back into working together to solve the problem, but she has caused a problem for me right off the bat which is rather frustrating,” Regbo says. “But we’ve both done things wrong – in fact I’ve probably done something that’s incredibly wrong-er than what she did." 

Here’s what else Regbo had to say about Francis and Mary’s relationship as they finally get to rule France: 

Zap2it: Catherine doesn’t seem too happy about her lack of power. 
Regbo: She has to answer to me in a way, but she is still in a position to give me quite stern advice and as a mother tell me when I’m being an idiot. I think even one of her lines is "You’re an idiot.” There is still a working relationship and she is my mother, but yes, being Queen Mother doesn’t quite have the same ring to it as Queen. That’ll be an issue for her – trying to maintain her power because she has her own motives. 

Plus, she’s his mom. 
Mothers are always right, rather annoyingly. I’ve yet to be proven wrong on that theory through experience with my own mother – she’s never been wrong about anything. Catherine still has that experience and she’s wiser than we are and she does know better and sometimes that does mean doing things her own way, without us sometimes even knowing, in order to protect us and the country and the crown. 

How is Francis’ relationship with Bash? 
The conflict between us was caused by the fact that our power was uneven – he was never going to get that crown. But now the power has sort of been realigned – although I am now king, there isn’t this third party between us. It was our father who was causing the rift between us so now Bash is actually a great asset for Francis, to have someone that he can trust. They share blood, although by our show’s standard that doesn’t actually account for that much. But having someone around he can trust who isn’t going to stab him in the back is going to be a great asset. 

Bash as an asset is great, but things are looking bleak for France as a whole. 
The country that [Francis has] been handed isn’t particularly in good condition. It’s been ravaged by plague and famine follows plague, and that costs the country a lot. He’s found that being the king isn’t going to be easy right off the bat. You can’t just sort of roam around the country on the peasants’ shoulders laughing and giggling – I don’t even know why that entered my head, but there you go. He has to answer to people with money and resources and those people don’t necessarily have his best interests at heart. 

One of those people is Lord Narcisse. 
He’s got food; we need food; he’s a bastard. [Francis and Mary are now focusing on] managing his needs and placating him to get what we want while also trying to manage the anger at the fact of what Mary did [to his son]. He plays a major role in French politics and so I can’t just do what I want. I have to do what he wants as well, and that’s tricky.

(Source)