Each of the territories is a themed caricature - a desert region with only mining industry, a super-fertile region where everything grows to huge size, a Las-Vegas-like tourist region with casinos, etc. Much of this is just side flavor in the story, but two territories in particular have more significance. One is Furawau - a Middle-East-style region with large oil reserves, made very rich by that bounty of natural resource, and controlled by a single large family. The other is Suitsu, where travel restrictions and a very strict division between nobility and commoner have resulted in economically poor conditions and rebellion.
The story takes enough twists and turns that it's not easy to talk about it without spoilers, but it's probably no surprise to anyone that Jean gets caught up in intrigue that affects the entire kingdom. This takes the form of a coup, timed to prevent the ascension of a new ruler to the throne. Prince Schwann, the heir apparent, is dismissive of ACCA and plans to dismantle it. The powerful figures behind ACCA have no intention of going quietly.
In the last few episodes, particularly the last one, the path the story took isn't particularly credible. There are a lot of plot twists, which are very exciting but not very believable. Perhaps with a bit more explanation and/or groundwork to set up the sudden shifts, it would have felt more realistic. As it was, it felt like deus ex machina at the end.
ACCA: 13-Territory Inspection Dept. has some fairly pointed commentary on social and political systems. Condemnation of the restriction of freedoms in Suitsu is an obvious one. Strength through diversity is emphasized, as ACCA incorporates people and resources from all 13 territories. The dangers of autocratic rule is a central theme, both in terms of the kingdom monarchy and the hereditary control in Furawau and Suitsu. At the same time, there's a heavy emphasis on maintaining culture and tradition, exemplified by the fact that no one advocates actually overthrowing the monarchy - just replacing the prince.
There are some fairly silly side themes in ACCA: 13-Territory Inspection Dept., too. Many of the characters have a fascination with sandwich bread, which for some reason is only made in the Badon territory. Jean is a heavy smoker in a society where almost no one else smokes, and giving him gifts of territory-specific cigarettes becomes a plot device. These sorts of things add a lighter side to the series - silly, yes, but I think it mostly worked well to balance out the heavier intrigue plot points.
I thought ACCA: 13-Territory Inspection Dept. was reasonably good for a short series, despite what felt like clumsy writing in the plot twists at the end. Not bad if you like the intrigue theme.
