Alrighty, finished 王侯貴族の愉しみ. Unlike the previous drama CD booklets, we had only one POV (Kaito) and his observations of three different men. This is set during the Spain arc, somewhere in the first three chapters of volume 11, so those men are of course Leo, Alonso, and to a small extent Vicente. (This might be set after 一途な瞳?)
We start the story with Leo fussing over Kaito like normal; they make such a great pair of brothers, I’m glad Kaito has someone he thinks of as an 弟 other than his actual brother. Leo gives Kaito some water buffalo cheese to eat (would that have been a thing back then? I don’t know much about water buffalo…), which Kaito uses to wow Leo with his culinary skills after adding a little bit of olive oil. Vicente eventually enters, and after some back-and-forth Kaito decides to watch Leo’s sword practice with パチェコ, one of the guards at El Escorial.
Well, パチェコ is just coming back in after an outing with Alonso, who immediately pounces on the idea of giving Leo a few lessons, which Leo and Vicente vehemently turn down, lol. Kaito inadvertently suggests a contest to see who has the better sword skills, Alonso or Vicente, to cheer Alonso up after all the ribbing, which he pretty much immediately regrets after he sees how badly Leo’s going to take it to heart after Vicente inevitably loses. (Neat callback here: Kaito realizes that Alonso’s style is just like ベナルール・ド・アルトヴィッチ, that French envoy we met back in volume 6. Both trained in an Italian style, apparently.)
So attempting to salvage the situation, Kaito realizes that Vicente’s best chance of winning lies with the maneuver Geoffrey pulled back in volume two’s La Rochelle when he disarmed Vicente. At a certain point of the fight he calls out 「ラ・ロシェル！」, which causes Vicente to freeze up and lose the match. 
Leo explains the dirty trick to Alonso, who immediately cottons onto the idea and starts showing パチェコ how to do it so they’ll be prepared against the dirty Englishmen using such tricks. Everyone ends up happily at the end sans Kaito: Vicente’s touched that Kaito wanted to help him win, Leo’s happy with Vicente’s honorable loss of not using cheap tactics, and Alonso has a new trick to play with.
Kaito, on the other hand, has been spending the entire story feeling anxious over his growing affection for the Spain gang and not wanting to betray his England friends, and this latest thing just really compounds it all. He’s worried that if Geoffrey or any of his English friends ever have to meet Alonso in battle, they’ll have already lost their one chance of not dying since Alonso will be on the lookout for it. The story ends with him slowly starting to accept that he loves both groups of people, and just really doesn’t want anyone to die in war.
This whole story was pretty depressing. 
All of Kaito’s POV Spain arc stuff is; for admittedly good reason, but one day I want to read the AU where he’s happy to be there. 