When Daniel and Victoria Van Beuningen first toured their future home, a quiet villa in the Polish city Wroclaw, it had been abandoned for years, its windows sealed up with bricks. But something about its overgrown garden spoke to them. They could imagine raising chickens there, planting tomatoes and cucumbers. They could make something beautiful out of it, they thought — a place where their children could run and play.

They moved in knowing very little about what happened at the villa before World War II, when Wroclaw, formerly Breslau, was still part of Germany; or what occurred there during the war, when Soviet forces held the city under a brutal siege; or even what became of the house during the war’s aftermath, when hundreds of thousands of local Germans were forcibly resettled from what was now Polish territory. All their neighbors could tell them was that the villa had once housed a Communist newspaper.

Still, the couple wanted to know more, and their inquiries eventually led to the Meinecke family in Heidelberg, Germany, elderly siblings who said they were born in the home. Over a long afternoon, they showed the couple pictures of the place from happier times before the war, but they also offered the Van Beuningens a surprising warning: The couple might find the remains of some German soldiers buried in the garden. Maybe a few, maybe more; they couldn’t be certain.

The Van Beuningens didn’t quite know what to make of the claim, but it suddenly sounded more plausible when Daniel, digging a trench for a water pipe in his backyard, unearthed a Nazi-era helmet. It was around that time that Victoria received an unexpected knock on their door from, of all people, an archaeologist. His news unsettled the Van Beuningens even more — he had found documents that described an entire “war cemetery” located at their address. Could someone return to investigate? It was perhaps a coincidence of timing, but it was clear to the Van Beuningens that the answer had to be yes.