After Arnon Goldfinger’s German-born grandmother died, he helped clean out the Tel Aviv flat where she’d lived for decades. Among the dozens of pairs of gloves and ratty fur stoles he found something unexpected: papers and photographs detailing the time his Zionist grandparents toured Palestine in the 1930s in the company of a Nazi and his wife. And not just any Nazi, but a dear friend of theirs, who happened to share Goldfinger’s grandfather’s gung-ho approach to establishing a Jewish settlement in Palestine. Goldfinger discovers that at one point his grandparents’ friend Leopold von Mildenstein was Adolph Eichmann’s boss. Although he’s too gentle and plodding a filmmaker, Goldfinger makes a fine detective and the intrigue deepens when he discovers the couples actually resumed their friendship after the war. What makes The Flat a scary little documentary of wider interest is how easily a horrifying truth was neatly buried in just one generation—von Mildenstein’s daughter thought he was a journalist—and would have remained so if it hadn’t been for Goldfinger’s considerable curiosity.