August

I put down the phone and just stand there, completely still. "Mum? What is it?"

Everything in this house is Grace's business. At eighteen, she's allowed secrets, but no one else. When I don't reply instantly, it's not good enough.

"Mother, who were you talking to?"

"Sorry." You know those moments when your head is bursting with too many thoughts to form the words? My eyes fix blankly on something — a spot on the wall, an empty mug — not seeing them. "That was Jo. Something really odd's happened. Rosie's gone missing."

Living at opposite ends of a small village, with daughters at the same school, Jo and I belong to a group of mothers who meet now and then. I know that she's married to Neal, a renowned journalist, whose handsome face I've seen looking out of our TV screen more times than I've actually met him, reporting from the middle of war zones. That they have two daughters, drive new cars — her black Range Rover and Neal's BMW X5 — and live in this big, architect -designed house, which I've been inside only once or twice. It's a friendship that extends to the occasional coffee or gossipy lunch, but it's Rosie to whom I've found myself drawn. They're the same age, Grace and Rosie, A levels behind them, the start of hard-won university places a few short weeks away, but the similarities end there. I know Rosie as a shy girl, quieter than Grace's crowd and who shares my love of horses.

Grace rolls her eyes. "She's probably just hanging out with Poppy and hasn't told Jo, because she wouldn't let her. Poppy's a slut."

She says it good-naturedly, like idiot or moron, but it's an ugly word on my daughter's lips. The reprimand's out before I can stop it.

"Gracie ..."

And then my mind's wandering, as I try to imagine what's happened to her, seeing the clear eyes she hides behind the fair hair that falls across her face.

"Seriously, Mum. You haven't met Poppy. Her skirt's so short, you can see her panties. And she snogs anything — even Ryan Francis."

Ryan Francis is the worst male specimen on the planet, according to Grace, who's yet to explain exactly why.

"But Rosie's not like that, surely?" I struggle to imagine the Rosie I know snogging an indiscriminate anyone. She has a gentleness I've seen with my horses, which comes from her own instincts. They mooch peacefully around her through the long grass, like she's one of them.

"Duh. I'm talking about Poppy, Mother. But, you know, peer pressure and all that ... I wouldn't be surprised...."

Alarm bells start ringing. What if she's right and Rosie's got in with a bad crowd or, worse, been persuaded to run off with some less than desirable boy? Should I say something to Jo? Then I see Grace's face. She's winding me up.

"Well, whatever," I say, annoyed, because this isn't something to joke about. "If you hear anything, let me know. Jo's really worried. She hasn't seen Rosie since yesterday, and her mobile goes straight to voice mail. If it was you, Grace, I'd be out of my mind."

Grace hesitates. "I can get Poppy's number, if you like." Flicking her long red hair over her shoulder as she busies herself texting.

Thanks to the interconnectedness of today's teenagers, in a few seconds she has it. "I'll send it to your phone."

Half an hour later, I get through to Jo. She's jittery, not surprisingly, only half listening, her mind jumping all over the place.

"Not Poppy Elwood?" I can hear from her voice, she's shocked. "Oh, Kate, Rosanna wouldn't be friends with her...."

"Well, according to Grace, she is."

"Oh my God ... " I can hear her imagining her worst nightmare, that her daughter's run off or eloped. Jo's inclined to fuss over her daughters, even though Rosie's eighteen and about to leave home. "The police will find her, won't they? You hear about this kind of thing happening ... but they always do find them, don't they?"

"Try not to worry, Jo." Sounding far more confident than I feel. "I'm sure they will — if it comes to that. She'll probably walk in any moment with a perfectly reasonable explanation. But why don't you call Poppy?" I remind her. "You never know. She might be able to tell you something."

"Yes, I suppose I should." She's quiet. "I still can't believe she's friends with that girl."

I know how she feels. All mothers have them. The friends who threaten everything we've ever wanted for our daughters with another way to live, another set of standards, which we're terrified they'll prefer to ours.

"She can't be all bad, or Rosie wouldn't be friends with her," I point out. "And at the end of the day, she's your daughter. She knows what's right. She's not stupid."

Jo's silence echoes my own hesitation, because it's not something Rosie's even hinted at, but I'm curious.

"I was thinking. ... Does she have a boyfriend, Jo? Only if she does, he might know something."

"No. She doesn't. She's put all her time into studying. Not like ..." She leaves the sentence open-ended.

"I'll get off the phone," I say hastily, ignoring her gibe at the students who work hard but play hard, too. Like Grace. "She might be trying to call you. Will you let me know when she comes home?"

Rosie will turn up. I'm sure of it. I have a gardener's inherent belief in the natural order of things. Soft-petaled flowers that go to seed. The resolute passage of the seasons. Swallows that fly thousands of miles to follow the eternal summer.

Children who don't die before their parents.

After I've spoken to Jo, I call upstairs, "I'm going riding, Grace. ... Want to come?"

"Going out," comes the muffled reply from behind her closed door. "Sorry."

Another day, her indifference might irritate me, but not today. Grace likes to ride out early, when the air's still cool and the landscape quiet. Thinking time, she calls it. And it means I can set my own pace, instead of being swept along full tilt on teenage time, when the entire day happens randomly and at speed — until you arrive at the social -life part, which is what it's all about. And today I need time to clear my head.

It's hot for late afternoon, a heavy, muggy kind of heat that goes with the clouds bubbling up in the unstable air. As I walk across the field, the horses are lethargic, lazily flicking tails against the flies, momentarily interrupting their grazing to lift their heads when they hear me coming.

Apart from my own semiretired Reba and Grace's almost outgrown Oz, the horses here arrive with problems, according to their owners, who pay me well to reschool them. It fits around my work designing gardens, and, anyway, horses are my lifeblood.

Whatever else is happening in my life, they keep me grounded. It's their beauty, their spirit, matched by no other creature. The way they move, the warm, velvet softness of a muzzle against my cheek. There's no pretending with a horse. They read your body language. Know what you're thinking before you do.

Today I'm riding Zappa, a large gray I've been warned is unpredictable and dangerous. Whatever, as Grace would say, rolling her eyes. He's one of the most beautiful horses I've ever seen, with straight, elevated paces and dark, intelligent eyes. The kind of horse that hears your every whisper, responds to the smallest shift of balance. A dream.

This supposedly dangerous horse stands sleepily while I tack him up,...