The episode started with a recap of last episode's big twist reveal (a very bold choice on the author's part considering the chemical is extremely infamous in real life Japan). This episode continued with how the whole village was artificially constructed for a single purpose, and showed that almost all the villagers were German soldiers who saw our protagonist as English spies. That explained why Germany was reluctant to accept aid from England with all the strange cases around the area. So even though the German emperor was the Queen's grandson the relation between the two countries weren't very good apparently.
Sullivan was a prodigy, she could read fluently at the age of 3 and understood advanced chemistry.
A little poison gas wasn't a problem to a hell of a butler.
There are still a number of episodes to go, I guess we'll see how they escape the village and how the Phantomhive servants fare against German soldiers in combat.