The cruelest truth of parenting: If you do it right, they leave.

I’d done my reading. I knew that from the moment I got that baby in my arms, my job was to prepare her to go. I understood. I’d done it myself, to my own mother. So I concocted a foolproof evasion.

As our eldest approached adolescence, I created an adventure so adventurey that it would foil the designed entropy of human development.

When our kids were five, nine, and twelve, we moved to a tiny mountain town in Costa Rica. For the obvious reasons—slow down, step outside consumer culture, blah, blah, blah. I wanted to live a life a little less obsessive Type A, and for our family to spend less time at practices, more time together.

The plan was clearly brilliant. In our new world, our kids were more a team than they’d ever been back home.

“You guys will not believe how milk works here!” Hannah, Harry, and five-year-old Ivy burst in from a mission to the grocery store, where they had discovered giant, metal silos. Strictly local and straight from the town’s dairy, the silo milk could be dispensed into a vessel of our own choosing. We’d never experienced milk that had been, so recently, encowed.

The early weeks were filled with such marvels, shared among ourselves. We were all we had.

In no way did I intend “I want us to be closer as a family” to translate to “Let’s take our adolescent daughter to a place where she can’t speak the language and knows no one; then she’ll have to stick with us.” But the fact remains: Speaking no Spanish, we moved to Central America, and to a house so isolated you had to walk ten minutes to find another person. Hannah was almost 13 — time to fly, little bird — but I had her now.

And then, without warning, she vanished.

My own teenage disappearing act had been strictly by the book: into friends and football games and anyone- is-more-exciting-than-my-parents. As an adult, I thus assumed that adolescent separation required a destination—a world to separate to.

But we were strangers in a strange land and Hannah had no not-us destination. She disappeared in place.

Our rented mountaintop house was built by people who liked each other, who wanted to be able to chat no matter what else they were doing. Kitchen, living, and dining rooms were all one inviting space. Sliding doors to the wraparound deck opened wide, erasing the distinction between inside and out. It was a little like living in a sidewalk café. Everything about our house was about being together within it.

Hannah’s loft bedroom was the sole exception, its own little world. Her space came complete with tiny bathroom and its very own picture windows from which to gaze at the sweeping view. She claimed her loft with wonder. “How can I know this is what I always wanted, when I’d never seen it until now?”

The space was a perfect match for the other thing Hannah had always wanted.

“I have so much time here…I can read anything …”

Hannah made her bedroom, this lovely top-floor viewpoint from which you could see the world, into an escape from it. In this house that was designed around being together, Hannah found a way to be apart. She turned 13 up there, moving into solitude as if it were some kind of destiny; it didn’t have the feel of a phase.

She ducked away from us, spent her time instead with Salinger or Austen or Allende. We missed her.

“Hannah, do you want to play…” Harry or Ivy would begin. Their big sister was polite, always.

“No thanks,” she said over and over, as she slipped upstairs after school, after dinner, after anything, just when we thought we might keep her for a while. “You guys go ahead without me.”

Hannah vanished in October. She was never mean, but we could tell she was being patient with us.

Our family at its best is jolly and jokey, with lots of flopping over each other. Hannah stopped flopping. I could feel her counting the minutes at dinner, and imagined her internal monologue: Will Mum be annoyed if I leave now? What about now? I’ll finish eating, then count to 100.

Ivy missed her the most. “Hannie, do you want to do my nails?”

“Maybe tomorrow.”

Harry was perplexed. His bookish sister hadn’t always quite made sense to him, but she had always, at least, been present. “Mum, doesn’t Hannah even like us anymore?”

Since Hannah’s first day of kindergarten I’d been steeling myself for my own separation heartache. Narcissist that I am, I’d never quite put together that our younger kids would hurt, too. How do you explain to a five-year-old that her sister’s brushoff is developmentally appropriate?

The mists that rose up our hill from the lowlands provided the ultimate now you see it/now you don’t. The view from our windows started at the guava tree and went down down down—past cows, pasture, forest, foothills, and finally to the thin, sparkling band of the Gulf of Nicoya. Several days a week, the mists climbed up from the gulf. In reverse our view would narrow, until even the guava tree disappeared and our house stood alone inside a white cloud.

I imagined the mists enveloping my daughter. I didn’t know how to keep them from coming and, once they were here, I didn’t know how I would find her again. I worried that one day, as they retreated down the mountain, the mists would take Hannah, too.

Eventually we got used to her being gone. The littler kids stopped asking. Months passed.

One April afternoon, our hillside sparkled impossibly green. The sun had burned away the mists and shone now on a world so bright and new you almost didn’t want to look directly at it. Hummingbirds hovered, and all manner of background wildlife had set to chattering and chirping. The soundtrack of our life would not have been out of place at a Seattle day spa.

I was in the kitchen, making chayote soup in a non-obsessive manner. I had told Ivy I’d be happy to stop cooking and play with her—all she had to do was stop saying my ideas were stupid. But Ivy was stuck in the groove of her own irritability and showed no signs of exhaustion. Harry and Daddy were out, Hannah was reading as usual, and there wasn’t anything to do up here, ever. Mum was boring and all of her ideas were…

Hannah was up in her loft, deep in One Hundred Years of Solitude. After the slow start and the revelation that this book was going to be way weirder than anything she’d ever encountered, Hannah was hooked. We’d barely seen her for two days.

Ivy finally got to the heart of her problem: “It is SO STUPID that Hannah never wants to play anymore!” By now, I was annoyed, too. What the hell? We’d brought Hannah halfway across the world, and she couldn’t be bothered to come out of her bedroom?

Then, from behind the foreground pulsing of Ivy’s frustration, I heard a tiny arrhythmia. A sad little sigh, the snapping of the book closed, the standing up out of the window seat and facing the world. The barely perceptible background sounds of resignation.

After a pulling-it-together pause, Hannah appeared at the top of the stairs. Ivy and I watched her descend. Hannah’s jaw was set firmly and her ponytail did not bounce.

Finally, she stood in front of Ivy, hands on hips. Ivy glowered up with her storm face on. Hannah looked down. Steely blue eyes met flashing brown. Hannah cocked her head to the left and added a brisk tapping of her right foot.

Any moderately attentive adult could see that Ivy had a full-on tantrum lined up; all she needed was someone to pull the pin.

“Ivy,” started Hannah. I cringed. Should I step in? Divert? Had Hannah, after all these months of adolescing quietly, finally turned the corner to the explosive part? Had I been worrying about the wrong pin?

“Ivy. What you need…no, actually, never mind you …”

Pause.

“What this house needs…”

Ivy glared.

“Is some strawberries. I have totally had it with the lack of strawberry pie in this house. It’s insane. I’m going outside.”

Patches of wild strawberries dotted our hillside. We’d eaten a few, but as a concept they’d failed to take hold. It might have been a girl-next-door thing: the berries were always there. Why bother with them, what with all the sexed-up mangoes and papayas constantly throwing themselves at us?

Hannah marched to the kitchen and grabbed all the plastic storage containers we owned—four.

“I am going to need all of these because the berry deficiency we are dealing with here is acute.” She shoved her feet into her flip-flops.

And then, as afterthought, “Ivy, you can help if you like.” Hannah held out her hand for a millisecond but did not coax. She dropped a container as she left, closing the door behind her and not looking back.

Ivy stood her ground, eyes narrow. Then she walked over, grabbed her faded ladybug boots, and snatched up the Tupperware. “Yeah,” she threw back at me on her way out. “It’s insane.”

I watched them out the window. After a while, Hannah flopped to the ground and lifted her face to the sun. When Ivy wandered near, Hannah opened her eyes, peered into her container and picked out a perfect berry. She pulled her little sister into her lap, and fed her like a baby bird.

Was she back? Was she toying with us? Would a tiny lecture along the lines of “It’s about time” be out of place?

When my girls finally came inside, I said this: “Yum!”

I’d known the basics about the leaving. But I hadn’t known it would hurt quite so much, or that it would affect our whole family. That no clever gimmick could forestall the inevitable.

I know now that I couldn’t have hoped for a lovelier departure. Hannah had simply slipped away, wanting none of our delightful, familial hilarity. There was no yelling, and no doors slammed. It was our starter goodbye, and over the next years Hannah would vanish again and again—into friendships, boyfriends, politics—sometimes gracefully, often not. Rules would be broken, curfews missed.

I think about my own youthful goings-away. I went far, stayed away long, and, like my own daughter, was not always kind. And yet.

Three summers ago, I caught a cold that got worse instead of better. I got the pneumonia diagnosis two days before Ivy’s birthday and with a work deadline looming. I didn’t have time for pneumonia. Desperate, I called my mother’s house. When my stepdad heard the tears in my voice, he said, “I’m coming to get you.”

I stayed for a week. My mother and her husband fed me soup and made me sleep. They called my house and told my family to deal. I curled up. My mummy drew me baths. I was 44 years old.

If you do it right, they leave.

The cruelest truth, the truth we cannot trick away, is that it’s our job to let them go. But my firstborn’s adolescence taught me the most beautiful corollary. How had I missed it in the reading? Or maybe no one told me because no one wants to jinx it. They come back.

And when they do, being there—not judging, not furious that they left in the first place—is part of the job, too.

At thirteen, Hannah sighed, put down her book, and rejoined our family while I watched through a window. Being there doesn’t always look like the proactive parenting of the early years. When, after long silences, she wants to chat about a boyfriend or cry over the phone with the sheer exhaustion of being responsible for her own life, I listen. If she’s home, I get to tuck her hair behind her ear in the old way. And I’ll provide whatever haven she needs, 30 years from now, if she has to flee that life for a while. I will draw her a bath.

Almost four years ago, Ivy and I dropped Hannah off at university. Before flying back to our own coast, the two of us drove, weeping, around rolling countryside that looked surprisingly like the green hilltop where Hannah had first disappeared. But she was gone for good this time, two airplanes away from home.

Now approaching adolescence herself, Ivy doubled over in the rental car, hugging her sides for maximum drama. As she did so, her eye caught a small, wrapped package that hadn’t been there before: “For Ivy. If you need me, I’m right over here. Always.”

Ivy put the CD in the rental car’s player. Songs Hannah had picked out just for us filled the car and our chests and our lumpy throats. Hannah would never be gone for good.

If you parent your children with love but not hovering; if you give them roots and wings; if you share yourself (but not too much); if, in addition, the stars align or God smiles or pixie dust falls, whatever it is, that secret blessing outside our control … you’ve created the perfect friend. And the healthiest thing for that creature to do is … leave? I’m working with it, but honestly: That’s just bad design.