Part of why it works is because Reign has built on the rocks of its main characters. Despite Francis appearing to have drunk from the fountain of youth before puberty hit, he actually seems like a good guy. Mary also appears innately good, and completely reasonable. The people surrounding them might be insane and gossipy and backstabbing, but these two main characters act in a way that's sympathetic and, above all, sensible. Their actions are not over-the-top, but grounded in reality. A good example is their initial responses when Francis's ex-lover Olivia bursts from the woods, crying over a broken carriage and her murdered servants. Francis does feel a responsibility for this girl whose virtue he ruined, but first he comes clean to Mary, tells her of his past, and is upfront with his intentions. Totally a good guy thing to do. Mary, for her part, welcomes the girl even though she is clearly uncomfortable with the situation. Because Mary is a good person, she is kind to the poor besmirched noblewoman, and offers kindness when everyone else shuns Olivia.
But because this is a CW show, and in fact because this is TV in general, it's impossible to have two people behave well and allow people around them to respond in kind. After Mary lends her a dress, and offers an impassioned speech on how unfair it is that kings get to sleep around but maidens have no control, Olivia goes all crazy insane and tells Mary to her face that she still loves Francis and intends to become his mistress. Because Olivia "knows" what Francis likes, if you catch her drift, in a way Mary doesn't. Because Mary's all not ruined yet. And when Mary very gently asks Francis to send the girl to another house, a house far away in Paris where Olivia's reputation is not known, Francis agrees. But that's before Olivia force-kisses him, uses her wily ways to try and seduce Francis, and manages to be moved into the castle. This triangle is further complicated when Evil Anne Queen spits poison into Mary's ears, outing slutty LiW's affair with the king and offering Mary a twisted look at her possible future as the Queen of France.
Which is made all the more delicious when it is revealed that the Evil Anne Queen is behind Olivia's return, and that's she's essentially prostituting this young woman in an attempt to destroy Francis's engagement. It's a bonus that the young lady in question wants to be prostituted to Francis, but still. Quite the morally gray area. But it works, in the sense that it drives a wedge of distrust between the burgeoning lovers Mary and Francis. They quarrel, and Francis stomps off while Mary runs to the lake, where Bash and a flagon of booze sit waiting.
And Bash. Oh Bash. Bash has very subtly flirted with Mary in this episode and in the first, but nothing has really been made of it till now. Mary, after drinking too much and pouring her heart out to him, ends up kissing Bash in this episode. Which is delightful in many ways, because it's Bash, but is also frustrating because this is a plot point that could have been drawn out longer and made all the more satisfying when the kiss did inevitably happen. Bash is a naturally charismatic actor, and is completely likable and sympathetic, which is incredible because he hasn't been given much to do. As a character, he's still rather fringe, and yet he's completely magnetic. It's understandable why Mary would be drawn to him, because between the two brothers Bash is A) a man, and B) more free a better match for Mary personality-wise. He also has Joshua Jackson-level powers with his eyes, managing to make a simple look at Mary sum up his entire appreciation for her, conveying his respect and love for her in a glance. But he hasn't reached Pacey-kissing-levels, where that attitude is transferred in an incredible weak-at-the-knees kiss. Perhaps if this had been drawn out more, if we had gotten more shots of his uncannily warm blue-eyed gazes at Mary, the kiss would have had a better payoff.
Francis of course notices the snogging, which prompts him to show cold anger at Mary and to go shag his mistress in the boathouse. Those poor kids just can't ever be happy. Even Mary immediately tells Bash she shouldn't have done that, leaving him rejected as well. There's just no joy for the rich and royal.
It does appear that Bash will be getting more screen time though. His relationship with the pagans in the Bloodwood is discussed further, setting up some nastiness for future episodes. Bash has cut down two of their sacrifices, and now they pagans demand he make one in return, or they will come to castle and choose a sacrifice for him. A sacrifice to what? Well, apparently there's a creature in a cave, a creature that demands fresh blood, or else it sucks the life from the pagans in the wood. I'm not going to get too excited here, but could this be the vampire TV deserves, but isn't giving us right now?
-Innocent LiW, whose name is officially changing to Gold-digger LiW, decides she can't live with regret and wants to make out with the cheeky devil of a kitchen boy. This happens after she tries to go after an old Hapsberg (giggle!).
-Mary joins the intrigue game. Evil Anne Queen caught the silly braided LiW apparently stealing from Mary, and blackmailed her into stealing Mary's letters and delivering them straight to the Queen. It turns out Mary was behind the whole thing! Nice scheming.
-Olivia has the only French accent in the entire French court. This amuses me, as it's clearly a ploy to make her even more sexy.