There are mysteries, the regular whodunits and their more sophisticated contemporaries, and then there’s the truly mysterious. The two words may share a root, but I argue that in film, they often have very little to do with one another. That isn’t to say a mystery can’t also be mysterious, but there’s something different at the core. A mystery has a solution, an answer, and the uncovering of that solution is often the point.
The story begins, we ask “why?” or “how?” or “who?” and then we follow Holmes until we get our answers at the end. We sit back with a self-satisfied smirk and congratulate ourselves when we insist we had it figured out all along. But with the mysterious, it’s the question that matters.
With the mysterious, answers are superfluous. The story begins and you ask yourself the same things, only it’s likely you never get your answers. Art like this is polarizing because it doesn’t cater to our need for gratification, our desperate desire to know. We live in a world where it’s so easy to know absolutely everything (“Siri, who killed Sir Charles in ‘The Hound of the Baskervilles?’”) that it can be infuriating when art refuses to bend to this whim. This is the uncomfortable space where Picnic at Hanging Rock makes its home.
Like Twin Peaks and more recently The Leftovers, Picnic at Hanging Rock is absolutely in love with its central mystery. In this case, three girls and one teacher disappear without a trace while on a Valentine’s Day picnic. We watch the girls, aflutter with excitement, we get a peek at their dreams and desires as they muse about life, love, and the world around them. And then three of them are gone and a teacher along with them. What follows is less about solving the mystery of their disappearance and more an exploration of what happens to everyone left behind. 
To put it plainly, Picnic at Hanging Rock doesn’t really care why the women disappear. It is not interested in telling us this. Instead, information trickles out in poetic voice-overs and dreamy editing and it’s up to the viewer to try and parse out what it all means despite the fact that it often feels like we don’t even have all the pieces to the puzzle.
After about 30 minutes or so of the film, Miranda, Irma, and Marion vanish without a trace. They are, as Mlle. de Poitiers likes to say, like “Botticelli angels.” To have seen them at all, Miranda in particular, feels like a gift. We repeatedly hear each of them, often in no more than a whisper, espouse philosophical aphorisms, quotes from Shakespeare and Poe mingled in with their own ideas.
Marion, upon seeing the fellow picnickers from the top of the rock, wonders aloud that, “A surprising number of human beings are without purpose, though it is probable that they are performing some function unknown to themselves.”
Similarly, Miranda offers up her own somewhat Aristotelian view: “Everything begins and ends at the exactly right time and place.”
But when we get to Irma and Miss McCraw, Picnic ties the two seemingly polar opposites together through their philosophies. Without Miss McCraw, Picnic is only a story of missing children, youth that’s been snatched away too soon. It’s vital that she play a role here in order to speak to something bigger.
Miss McCraw, a mathematics teacher who’s shown to have an impressive knowledge of science as well, is stern, strict, and detached. While the children around her share valentines and giggle at the prospect of their outing, Miss McCraw sees only the absurdity of it all: “This we do for pleasure, so that we may shortly be at the mercy of venomous snakes and poisonous ants. How foolish can human creatures be.”
It’s not until they’re on the ride to Hanging Rock that we see how truly disinterested in relationships Miss McCraw seems to be. Coach driver Mr. Hussey tries to share some of his wisdom about Hanging Rock, but when he calls the rock “hundreds of years old” Miss McCraw quickly corrects him that it’s thousands of years old, probably a million years old or more. When he tries to agree that that was indeed a long time ago, she corrects him again insisting that compared to the relative age of the universe, a million years is quite young.
The point of this exchange is to show Miss McCraw repeatedly shutting down even the most polite human interaction. She clearly has no use for it. But even more importantly, it ties her to the girls because it’s only following this that Irma who pipes up to note that the rock has been “waiting a million years, just for us.”
As easily as Miss McCraw shuts out others with her facts, the girls just as easily turn her facts into something romantic, even magical.
Miss McCraw should be a complete outsider to these girls, but the mystery ties her to them instead. And when one of them is finally found, you’d think it might be her, but no. It’s Irma. Earlier, we learn from Edith that the last anyone saw of Miss McCraw on the rock, she was running up it in only her drawers.
The girls, on the other hand, are described by Edith as full of calm, walking into the rocks only to never be seen again. The mysteriousness here pulls the audience in two directions. Miss McCraw’s last appearance suggests terror and violence, while the girls’ suggests something more supernatural and unexplainable.
But again, only Irma comes back and she cannot (or will not) share what she remembers, if she remembers anything at all. Picnic prevents us from any clear answer. Had Miss McCraw returned, it would seem as if there was something special about those girls in particular and even if the film still refused to say what it was, we might be able to make more sense of it. But instead, we have this strange mixed group of competing philosophies, at opposite ends of the spectrum, lost together forever.
Picnic at Hanging Rock wants us to focus on this strangeness, to hypothesize, to wonder, but never to know for certain one way or another what happened. It simply doesn’t matter. It’ll only be through asking as many questions as we can that we can find not the answer to the mystery, but the heart at its center.