The Unknown Quantity (1919)

Mary Boyne, who made shirts at four dollars a week, had no place for love in her life - only despair and hate for the son of the man who had plunged her family into deepest distress. Peter Kenwitz loved Mary, but because he was a mathematician and a pessimist by trade, his love was as hopeless as her chance for happiness.

Unfortunately the movie The Unknown Quantity is not yet available on HBO Max.