Yes, I saw that there's a miniseries that covers a few more books in the series, I was keeping it for this summer. I'm curious about the fact that the tv series adapts this book in the second episode, despite the novel being the first in the series; was it just because the other story is more popular with readers, or did they change a few things in the adaptation?

I suspect that they probably ditched the whole beginning of this book -- it's hard to imagine how they'd transfer a whole year's worth of essentially uneventful apprenticeship, as well as the whole Guerande business, to the screen with the time and budget constraints usually available for small-screen productions anyway -- and Nicolas enters his first investigation as a young but promising and well-favored member of Sartine's police force. When they get around to "Blancs-Manteaux", they probably either just find another reason why he is sent to lodge with Lardin, or he isn't sent to lodge there at all but just takes up the case from the moment of Lardin's disappearance. À voir! :)

(He is also the Marquis de Ranreuil, after all, in the series -- so it's definitely not *entirely* faithful to the books.)

Based on the brief descriptions on Amazon and Wikipedia (FR), book 2 (= episode 2 of the TV series) deals with a plot against Louis XV and Mme. Pompadour. The makers of the TV series may just have concluded that this would make for a bigger "splash" as the opening episode?