My second Annie Baker play in two days was John, her newest piece, which I saw in its penultimate performance. Six – nearly seven – hours is a long time to spend with one writer’s works, but I felt every bit as enthralled as I had at The Flick.

No one would miss that these two are by the same writer, I think – there’s a similar style of minimal events unfolding in leisurely real-time, with lots of pauses (enhanced by Sam Gold’s masterful direction); also a shared language of quirky, seemingly open-ended and inconclusive conversational loops.

But in John, Baker is also exploring new (for her) territory. “Pirandellian,” said a friend of mine, captivated by the piece, as I was. (He was likely thinking specifically of a moment at the close of Act II – one of Baker and Gold’s great theatrical coups, it feels improvised, though it almost certainly isn’t.)

My own initial points of reference weren’t so high-brow – I thought of Arsenic and Old Lace (wonderful roles for two oddball older ladies), and Time of the Cuckoo (a young couple, hoping to mend their strained relationship through vacation travel).

What’s really different here – John seems to exist in a mystical, even religious, realm. Not that all the characters (particularly the youngsters) understand it, and perhaps neither does the audience. But the Bach underscoring (mostly from his liturgical choral works) that permeates the play suggests a profound spiritual vastness.

Initially, though, John looks like something else entirely. The set-up seems ripe for a horror movie, especially for those of us whose deepest fear is a quaint bed-and-breakfast (the kind of place Hummels go to die), with a talkative proprietor (Georgia Engel, in a career redefining performance).

That the action takes place in Gettysburg is a wonderfully mordant touch, and a hint of things to come – but for most of the first act, at least, life appears fairly straightforward. Elias and Jenny (the couple) are here to spend the weekend; Mertis (the proprietor – that’s Engel) fusses over them, and – mostly – everything seems right with the world.

Still, it doesn’t take long to realize that something – many things, really – aren’t as anchored as they seem.

Ultimately, I don’t think John is as consistently successful a play as The Flick. There’s a level of contrivance and manipulation here, as well as a number of fascinating elements – especially the magical realism – that aren’t fully worked through. Yet in some ways I enjoyed John even more, and a lot of it has to do with the production.

Sam Gold’s direction is full of extraordinary detail – the most mundane moments somehow have a vibrant life, and the piece as a whole feels almost symphonic. And then there are the actors, who – individually and together – are sensational. Christopher Abbott (Elias) and Hong Chau (Jenny) give performances rich in subtext and connection.

The play really belongs, though, to the two older women. Lois Smith is hilarious, brilliant, and biting as Mertis’s oracular friend — it’s a small-ish role, but she practically lights up the room every time she appears. In any other production, this cameo would likely run away with the show.

John’s trump card is Georgia Engel. Annie Baker, who worked with the actress before in her adaptation of Uncle Vanya, wrote John with Engel in mind. That’s quite a gift, and it turns out to be mutual, with the audience benefiting most of all. In John, Baker provides Engel, a beloved supporting actor, with her first major lead.

Georgia Engel and Lois Smith — two great actors at the peak of their powers

What Engel gives back, though, is more astonishing. Audiences are most likely to know her from The Mary Tyler Moore Show, where she played, with adorable ditziness, the long-suffering yet somehow indomitably cheerful Georgette Baxter.

Her ditzy, cheerful beleaguered-ness remains – but here, the now older and wiser Engel is also philosophical, heartbreaking, mysterious, and disquieting. Moreover, she manages all of it without seeming to do much of anything. If Baker is the hottest playwright in town (and I think she is), Engel is suddenly, at age 67, not only a star, but an important actor in American theatre – and even more unlikely, a new hipster icon.

It’s one of those minor miracles that occasionally come along, reminding me why I fell in love with theatre in the first place.