Liebling, weck die Hühner auf (2009)

Author Steffen Teuffel moved from Berlin to sleepy, 'dying' Brandenburg (ex-GDR) small-town Krummenwalde with his wife Beate, who runs the local beverage firm, and their kids: smart son Kai opted out of college and happily works in the only pub; his shallow sister Lisa lets a classmate obsess over losing her virginity to farm boys; kid sister Sophie attracts kids' attention by waving a gold coin she found diving into the town lake, until Lutheran vicar Juchem, who needs to pay for a new church roof, snaps it up and enlists Steffen's research skills plus knowledge of French to help him and bossy mayor Gerd Jänicke, who wants to revitalize the town, research the local archives concerning a legend about a Napoleonic regimental treasure being lost in that very lake the golden Napoléon came from and split it three ways.