Tonight's 'Da Vinci's Demons' has Riario and Da Vinci working together to stay alive in the new world. Somehow I doubt this partnership is going to bear any great fruit. But gamesmanship is the name of the, uh, game in this episode. Ima takes Leonardo to her room and tells him that soon he'll get into the vault of heaven (note: not a euphemism). Her room is familiar to Da Vinci, and she tells him they must become one together, which he interprets as marriage. But they're interrupted by her father, the golden god guy from the last episode, who thinks that Leonardo will die in the trials to get her hand.

Back in Naples, Lorenzo is getting the stuffing whipped out of him by Alfonso, who interrogates Lorenzo about his wife. Alfonso is jealous, which Lorenzo doesn't help by telling him it was his oral skills that won Ippolita over. When he's put back in his cell, he sees the ghost of his brother as he consults with Ippolita on how to beat the king's game, which involves him having one arrow to kill the wild horse that has a rope tied to it that will hang him if he can't take it down. She suggests he assassinate the king with the arrow, which will make her queen, though leave him dead. He continues to talk to his brother after she leaves, and his brother tells him he needs to think of who he hates more than anyone to steady his aim.

Leonardo is tasked with beginning the trials for Ima's hand. Leonardo must stick his hand in a box with a snake in it, which poisons him. Riario is tasked with surviving in a corn field where three predators will hunt him, while also getting the antidote for the snakebite. Lucrezia, on the road to Constantinople, questions her father's motivations as he showed no emotions in seeing his daughter for the first time when her assassin friend passes out. Al-Rahim shows up, having drugged the assassin himself, and wants to prepare her for a world in which the Book of Leaves has fallen into the wrong hands. He also brings her sister Amelia back to have a conversation, and Amelia tells her that the deaths will have to happen. She then rouses her assassin friend and the three make their way to Constantinople, where Al-Rahim tells her she can play a part in keeping the Book of Leaves from doing something terrible if she remembers her training, and there's a labyrinth, but it will all happen in the future, maybe.

Leonardo, struggling with the poison, is given "The Rope of the Dead" to drink by Ima, who then suggests they unite their bodies as one. Which leads to a sex scene where Leonardo flashes between Ima and Lucrezia. He then has an out of body experience as he's told by Ima to follow the three turtles. His ghostly visage sees himself as a baby and is surrounded by other spirits when he hears a voice calling him. It's Giuliano, who gives him a riddle. Da Vinci gets it right, which leads him down a new doorway. He sees the Mona Lisa in a museum, and talks with the skin-map man about why the painting is so important, as the skin-man man points out the background is odd. Hrm. He then sees himself as a dying old man, and old Leo tells him he can't fail and has to keep the Book of Leaves from the bad people, which is the least interesting version of this scene.

Riario wakes up in a cornfield covered in paint. After hiding from some noises, he's attacked by one of the predators, but Riario is able to kill him. He buries himself in dirt and is able to get the drop on another. The third, he goes aggro on, and it takes a minute, but he eventually gets the advantage and stabs the guy's eyes out. But the final task is nearly beyond him: he must kill Zita. And so he does, even if it breaks his heart.

Lorenzo is put to the test, and finds that he hates his brother more than anyone else, partly for dying before him. He kills the horse and survives. Leonardo tries to exit his vision, which proves difficult, and runs into Zita on the way out and she asks him to tell Riario that she forgives him. Leonardo wakes up and they've all passed their tests, but when Riario has a moment alone with Da Vinci, he tells him that if they don't get the Book of Leaves he will kill him.

Tonight's episode left out Clarice again, though -- as her subplot with Carlo is probably the least interesting storyline going -- that's a good thing. But while there was some exciting action (and shocking violence as the eye gouges were brutal), the whole Book of Leaves/end of the world stuff is a non-starter. It was evident from the writing credits that this was going to play on the show's master plan when it was revealed David Goyer co-wrote this episode, but -- though it was smart how the Mona Lisa reveal suggested that the background was more important than the foreground -- all this talk of what could happen is way less interesting that what is happening in the moment. We've been down this road before with other shows, and you have to be careful how you tease out what we're eventually building to as either we get there or the show gets cancelled, and how a show manages its major and minor goals makes this episode mostly feel like filler. Barrels were jumped, but there's no sense that anything moved forward.

The show has been playing with our possible sympathy for Riario, and that could get interesting as the person who most humanized him is now dead through the Aztec's guidance. We can see how the character could go either way, and it seems they are mimicking some of what happened with Walton Goggins' character on 'Justified.' That's a good character to steal from if so. This is the sixth episode of a 10-episode season, so it's understandable that this didn't push forward that hard, but we need to feel the build towards the end game of the season soon. With so many balls in the air, something has to touch the ground.