I'm sure anyone seeing this film will wonder just what is happening. This great cast made a very serious movie and were lines they could deliver powerfully dramatically and evenly to convey a whole range of emotions.
The plot is easily summarized. A reporter, O'Malley (Spencer Tracy) wants to write -- what? he's not certain -- a piece on an icon who people revere in the same way they might (say) Washington or Lincoln, The first part of the film is documents how to get to see the icon's wife. She's reclusive and her servants are dedicated to preserving her sanctity. What's behind this isolation? That in itself is a bothersome question for O'Malley. Something is not ringing right. She was the wife of a popular public figure. Why wouldn't she cooperate? As he digs, he finds he cannot write the story, at first because he does not know enough, and then because he knows too much of the wrong thing and finally because he suspects he does not know what is hidden from him and it is critical.
And as he untwists the Gordian knot that is presented to him, he finds there is duplicity and mendacity on every level. But nothing is as simple as it seems. Instead of writing about the icon, he picks the wife.
But that is not the depth of the film. The depth is revealed as we learn about the Hepburn character and Tracy's response. He moves from someone who can ignore genuine interest in him by a woman, (Audrey Christie), and seek his goal. What develops is first a genuine friendship followed by an admiration that transcends almost any other kind of relationship.
That is a very complicated situation to convey in the simple straight forward acting method of Tracy's (but he always manages to do what is required of him), and mysterious sophisticated quality that Hepburn always wears like some garment only given once by the gods who give such gifts.
This is not an easy exercise. Don't get caught in the datedness. Watch how the actors, directors and writers put together something that is admirable in its mixture of simplicity and complexity -- what others have called pealing the onionskin off the inion.