Karaoke and folklore in Kelso, Scotland Credit: Drew Farrell

In the auld Scottish ballad “Tam Lin,” the title character is a knight in a terrible spot. He’s been captured by the fairies and expects to be sacrificed this very Halloween, when their queen pays her tithe to hell. Luckily, he’s won the love of Janet, the bold girl from the castle down the road. She pulls Tam Lin from his horse as he rides in procession to his doom. The fairy queen (“an angry queen was she”) turns him into a snake, a bear, a lion, red-hot iron, and (depending on what version you read) molten lead, but Janet holds on to her man through it all, and he’s finally returned to human form—naked and free from the fairies’ thrall, if not Janet’s.

Playwright David Greig messes with that tale—satirically, romantically, and, for the most part, rhymingly—in The Strange Undoing of Prudencia Hart. The National Theatre of Scotland is giving his odd, sweet, smart update a don’t-miss staging at Chicago Shakespeare Theater.

Greig’s Prudencia is the sort who’d not only be familiar with “Tam Lin” but with every one of its many medieval iterations. She’s a scholar specializing in the ballads of the Scottish Borders region, where proximity to England meant centuries of war, plunder, and song. Her PhD thesis, she says, was about the “topography of hell”—a place so often visited in Borders lore that it can apparently be surveyed and mapped based on the textual evidence.

The scene of Professor Hart’s undoing is the little Borders town of Kelso. She’s driven through a snowstorm to be there for a learned colloquium titled “Border Ballads (Neither Border nor Ballad?).” All her academic rivals are in attendance, too, staking out post-post-structuralist positions involving vaginal rivers and arguing for working-class performativity as the next big thing in folkloric inquiry. A prim and earnest traditionalist, Prudencia can hardly stand it. In fact, she finally fails to stand it, interrupting her own presentation to ask her colleagues, “Why don’t any of you believe in beauty anymore?!”

Chief among the barbarians, as far as Prudencia is concerned, is Colin Syme, the working-class performativity man. A jovial creep with a motorcycle, a Hawaiian shirt, and the sensibilities of the habitual conventioneer, Colin comes right out and tells Prudencia that modern scholarship is a game. Then he calls her a “librarian” for refusing to join in.

Naturally, the storm turns into a blizzard, and all the scholars are snowed in together for the night.

And naturally, also, there are some delightful scenes of small-town debauchery—not to say, karaoke. But that’s not what Prudencia Hart is about. Strangely imprudent for a woman with her name and knowledge of Scottish traditions, Prudencia leaves the party at midnight in midwinter during a full moon. A very dangerous moment in a spirit-saturated culture. And sure enough, she runs smack into the hands of a very dangerous individual. Not the fairy queen, though there’s more than a bit of Tam Lin in her situation, but Satan himself.

I’d love to tell you the tale all the way through to the end, like a ballad—it’s so juicy, so full of unexpected turns as well as turns that are expected but play out in delightful ways. One passage in particular stretches toward Miltonian tragedy and—modestly, magically—achieves it. But I won’t go further. Suffice it to say that this is a comedy that every so often decides to break your heart.

The National Theatre of Scotland (the same bunch, by the way, that’s bringing the powerful Iraq War play Black Watch to Chicago starting October 10) has turned the upstairs black-box space at CST into a Scottish pub with a working bar (it’s a popular thing to do lately; the Broadway production of Once has one, too), and audience members sit at tables while the cast of five play around—and occasionally on—them. At one point cast member Alasdair Macrae, in the course of partying, curled up for a drunken snooze atop the table at which I sat with my wife, and she just naturally reached out to pet his head as if he were a napping child.

Melody Grove looks like Cillian Murphy’s attractive sister and gives Prudencia a passion that takes on admixtures of sternness or pain or love as the narrative unfolds. The others assume multiple roles and perform on multiple musical instruments, though Andy Clark is mainly an energetically obnoxious Colin and David McKay mainly a quietly unnerving Satan. Macrae and Annie Grace do characters, as well, but concentrate for the most part on the songs, of which there are many. At one point Grace sings, uncannily, in the manner of Sandy Denny, whose voice introduced me to “Tam Lin” decades ago. It was a haunting moment for me; I suspect it would be the same for anybody, whether they’d heard Denny sing or not.