“Past Perfect” is a spirited meditation on the elusiveness and inaccessibility of (Jewish) history as conveyed through sightseeing tours of “Jewish” Poland, a grandmother’s recollection of life in America during War II, and memoir-like “last moments” of a great aunt believed to have died in Treblinka. Shot almost entirely in contemporary Poland, “Past Perfect” lyrically portrays the relentless yet ultimately futile attempt to resuscitate a history literally gone up in smoke.