The monumentality of the Holocaust can understandably bring out the inner epic maker in a director — look no further than Steven Spielberg’s Schindler’s List or Edward Zwick’s recent Defiance. But an intimate drama that explores a sliver of the horrific experience can often resonate with additional force. The Israeli filmmaker Amos Gitai’s One Day You’ll Understand — an adaptation of Jerome Clement’s novel — is deliberately compressed in form and scope; as much a delicate drama of familial identity and subterfuge as it is an observation of wrenching historical fact. Jolted by the 1987 televised trial of the Nazi war criminal Klaus Barbie, a middle-aged French bureaucrat forces himself and his reluctant mother to confront the personal mysteries of the war era: What exactly happened to his grandparents? How did his mother survive the Occupation? What is his actual religion? That Gitai reveals secrets slowly, allowing subtly observed, gradually unfolding family dynamics between siblings, children and parents, husbands and wives to chart the dramatic flow rather than over determined plot devices is to his immense credit. Flashbacks of Nazi brutality make emphatic points, but they act as a necessary counterpoint to the staid domesticity of contemporary French life. The quietly grainy interactions between family members imply the pain that the overt violence expresses. Hippolyte Girardot, as the questing son, and Dominique Blanc, as his wife, impress through the fine-tuned subtlety they bring to their roles, but it’s the legendary Jeanne Moreau who centers the film. Calibrating her own restrained performance to the pitch of the ensemble, Moreau brings unstudied electricity to the screen. Like her director, she drives home consequential points through the crafty power of understatement.