Spoiler alert: Do not read until you’ve watched season three, episode two of “The Leftovers,” titled “Don’t Be Ridiculous.” 

Of all the things one might expected of “The Leftovers,” no one could have predicted a tragic homage to “Perfect Strangers,” the 1986-1993 sitcom. It’s so telling of the grace of “The Leftovers” is so aware that it is a television show — and more precisely, that it is aware of the sometimes terribly banal distance between television shows and real life.

“Perfect Strangers” and Mark Linn-Baker have been mentioned in “The Leftovers” before — in the world of “The Leftovers,” star Linn-Baker is the only one of the four regular leads not to have disappeared on October 14. For a while, the world thought all four had disappeared. But in the Season 2 premiere, a news item on a tabloid show is that Linn-Baker faked his own disappearance to start over — kind of — in Chihuahua, Mexico. The whole story is so oddly specific that it has the ring of truth. But among all people in the world, for Linn-Baker himself — playing himself — to call Nora Durst on the phone and ask her to meet him in St. Louis… the episode delivers this peculiar sensation between dreamlike symbolic logic and weirdly specific, bathetic detail that is characteristic of “The Leftovers’” particular power.

For all the things you can say about this episode, though — including the opening credits set to the “Perfect Strangers” theme song “Nothin’s Gonna Stop me Now” — “Don’t Be Ridiculous” succeeds because of Carrie Coon’s mind-bendingly sublime performance. It’s been a while since we’ve so intimately spent time with Nora, and the episode works slowly and carefully to break down each one of her defenses, her coping mechanisms — until she gets to the point where it is obvious, to her and to the audience, that she will choose to go to Sydney and bring $20,000 in cash with her to follow her children through to wherever. She is rational enough to know that she might just be incinerated, as she says, by the radiation process. But the pain of the loss of seven years ago has not abated — and Lily, the baby she found in the Season 1 finale and raised through Season 2, has been restored to her mother Christine (Annie Q). By the end of “Don’t Be Ridiculous,” Nora’s run out of reasons to keep going.

It starts with the preacher falling from the tower. His wife, a loyal believer, claims that he disappeared in front of her, faded out into the wherever beyond. Nora isn’t having it, and ferrets out the truth: He fell, bashed his head in, and was buried by his wife and (of course) Nora’s brother Matt, who is stubborn about the merits of belief even when it is toxic and unfounded. It continues at the doctor’s office, where she gets her cast cut off, hastily covers a tattoo on her arm, and then evades the doctor’s concern about how an orderly saw her slam the door on her own arm to break it with the glib “Why in God’s name would I do that?”

Then the mysterious phone call from Linn-Baker, who asks him to meet her in a St. Louis hotel that looks like a vertical labyrinth. The direction of “Don’t Be Ridiculous” is especially lovely because of how much it reveals about Nora’s mental state, and the shots of her in the hotel in St. Louis are of a woman dwarfed by inaccessible levels and layers — in one plane, when there are seemingly infinite stacked above and beneath her. (What’s with this show and hotels? Why does it feel like maybe “The Leftovers” is the only show that understands what it’s like to be in a hotel?)

For Nora, it really begins to unravel when she drives to Kentucky to see Lily, and spots her on a playground getting her sandbox shovel stolen by another kid. Nora jumps from her car to intercede, but when she returns the shovel to Lily, the girl has no idea who she is. Nora’s face just collapses, like something inside holding it up just crumpled to the ground. Christine confronts her, and Nora bolts — taking the shovel with her, accidentally — a child’s plastic memento mori.

Then there’s the ongoing technological malfunctions of the episode — from the airport kiosk, which asks her if she’s carrying a baby in her lap and won’t let her select “No,” to the GPS that won’t respond when she tries to navigate to Eminence, Kentucky (where Lily lives), to the parking garage at the Austin airport, that won’t take her prepaid ticket — spurring her to go outside and bodily heave the barrier up. It’s like Nora is perpetually stuck in Mercury retrograde — moving backwards, instead of forwards, out of sync with the world.

The final blow is discovering Kevin with the plastic bag around his head. It’s a scene that has a surprising sense of relief attached to it — like, finally, Nora and Kevin do not have to pretend to be fine anymore, when they clearly aren’t fine. (And Kevin’s attempts at life-affirmation mirror Nora’s efforts in that area in Season 1.) But it’s also so incredibly sad. Here are two people that love each other and have a loving family and a community that accepts them. But they are both too scarred. In desperation Kevin says to Nora that they should have a baby, and Nora laughs with this high-pitched hysteria — maybe because it is such a pathetic attempt to fill the void she feels, and maybe because if he’d asked two days ago, it could have been enough to patch their problems. Justin Theroux trying not to cry when she laughs and laughs is so heartbreaking, in and of itself. He so desperately and completely loves her and needs her. She is a lot less inclined to embrace that joy, and as she tells Erika earlier in the episode, it’s partly because she has a feeling she’s cursed.

So now Nora and Kevin are on their way to Australia — and something dark is waiting for them there. It’s very strange, how the episode jumps to two complete strangers in Australia to tell us about them, but when one affirms that yes, he is the town’s police chief and his name is Kevin, a pack of horseback-riding women set out to drown him. They must be looking for Kevin Garvey; they recite a scrap of apparent scripture from what must be, I guess, Matt’s gospel of Kevin (or someone else’s gospel of Kevin??). It seems rather inefficient to search for the messiah-Kevin by drowning all of the other ones — but then this is the power of gospel, Matt’s or otherwise. Belief drives people to do extraordinary things, sometimes beautiful and other times cruel. As usual, “The Leftovers” is so balletic with its plot twists that it is hard to imagine at all where this story will go. But with Kevin Garvey, Sr. stepping out of that ranch to bid the drowning ladies hello, we can at least expect father and son to reunite soon.