The documentary follows the trail of one large-scale Nazi looting operation. Provenance researcher Kathrin Kleibl and her colleagues are investigating the crime, and hope bring about justice one day. It’s her job to ascertain the whereabouts of looted art and return it to its rightful owners. Jewish families ordered to leave Germany were assured they could take their property with them. But often, all their worldly goods remained behind. Thousands of crates stored at locations like the port of Hamburg were seized by the Gestapo. Instead of sending the objects on to their owners, they were auctioned. The contents of entire households went under the hammer at the "Hamburg Bailiff’s Office" and in many other auction houses; the lots included valuable artworks. The auctions were blatantly advertised in newspapers. In Hamburg, they raised 7.2 million Reichsmark for the Nazis. A state-sponsored bargain hunt, says historian Frank Bajohr. The objects disappeared into the hands of private individuals, museums and dealers. In most cases, they have never been seen again. Who were the owners and who were the buyers? Kathrin Kleibl explains her mission: "The primary goal is to give these objects back to the families." In a research project funded by the German Lost Art Foundation, Keibl is hot on the trail. She has one key advantage, in the search: the Nazis kept meticulous records of their crimes. Kathrin Keibl has access to thousands of pages of auction reports, store ledgers and invoices. It’s an arduous task, but: "Using these puzzle pieces, we can trace the path of a theft from its original location to its eventual sale in Hamburg, " says Kleibl. The descendants of these Jewish families can now hold out some hope of recovering their property. The Koch family from Wiesbaden, for example, was forced to emigrate to London. But their crates, which contained priceless art collections including works by Nolde, Jawlensky and Klee, never arrived. What happened to their grandparents’ property? There’s a specific lead on one painting, but several changes of ownership and an art market that still remains largely secretive are hampering the search. As one member of the Koch family says: "If our generation stops searching, then this chapter will remain forever lost in darkness.” The valuable art collection of Johanna Ploschitzki from Berlin was also lost. Her belongings, which totaled 1,500 objects and included pieces by renowned artists such as Pissarro, Beckmann and Liebermann, was auctioned off over the course of three days in Hamburg. To this day, her descendants are hoping to recover at least some of the items. This chapter of German history is also posing a challenge to Dr. Ute Haug, provenance researcher at the Hamburger Kunsthalle art museum: In the year 1941, her museum bought eight paintings at an auction. But can these artworks be correctly assigned to the families they were stolen from? To find out, Ute Haug is also seeking help from Kathrin Kleibl.