Monica leans on a stone wall and waits. It is past midnight, close to one o'clock. A moon hangs above the island, so impossibly round and bright that it looks like a fake moon, a Hollywood moon, one made from paper and trickery and electric lights.
She feels sleep approach her, again and again, like a draft from under a door. Her eyelids droop, her head starts to fall, but she jerks herself awake.
When Aoife didn't come back after dark, not after Michael Francis and Claire came in, Gretta was up and down from her chair, to the window and back, wringing her hands, saying, Where's she gone, did she fall in the sea, do you think, why is it people keep disappearing? Monica had sent her to bed, saying she would go out, she'd find her. Everyone was tired from last night on the ferry. You'd have thought Aoife wanted her sleep, too, what with all the jet lag, but then Aoife had never been much of a one for sleep.
Monica went out into the dark. She walked to the north of the island, around to the westerly tip, back to the south. Calling and calling Aoife's name, searching everywhere she could think of. It reminded her of those times Aoife sleepwalked as a child. They would come in waves, Aoife's nighttime wanderings. Weeks could go past without a single incident but then Monica would wake and the bed next to hers would be empty, sheets pulled back, and she'd know that Aoife had been propelled to her feet by some unknown urge. Monica used to search the house — the bathroom, the stairs, the living room, the kitchen. She had found her, crouched by the dying fire once. Sometimes she'd be sitting on Michael Francis's bed. Another time, she found her out in the back garden, trying and trying to open the shed door, her eyes half open and dazed, in the grip of some somnolent drama. Their father had screwed bolts into the doors, high up so that Aoife couldn't reach them, to keep her from wandering into the street.
So here was Monica again, out in the night, searching for the wandering Aoife, ready to lead her gently back to bed.
She saw her from up on the sandy bluff: a tiny figure walking back along the causeway, which shone slick in the moonlight. Monica picked her way down — she has her Wellingtons on, under her nightdress — and is waiting here, at the wall.
As Aoife reaches the rise of the track, Monica calls her name. "Aoife!"
The figure of her sister jumps, puts a hand to her heart. "Who's there?" she says, and Monica is surprised by the fear in her voice.
"Oh. You scared the shit out of me. What are you doing here?"
"Waiting for you. Where've you been?"
"Out," Aoife replies, without stopping, moving past her along the track.
She flings her arm behind her, towards Claddaghduff. "There."
The dark is soft around them but she can see that Aoife's face is set, her mouth the slightly downturned line that Monica remembers so well from her childhood. Monica scales the wall, carefully, inexpertly, her Wellies catching on the stone edges, and runs to catch up with Aoife. "Were you phoning your boyfriend?"
Aoife makes a noise that means neither yes nor no and, without intending to, Monica stops. She says, "Aoife, listen."
Aoife stops, too, a few steps farther on, her back towards her.
Monica has surprised herself. She doesn't know what she wants to say, doesn't know what she wants Aoife to listen to.
"I ... " she begins. " ... about Joe ... " She comes to a halt. "I was just so ... Everything was in such a ... after what happened, you know ... " She takes a breath, then manages to say, "After what I did ... I ... well ... "
"Just say it," Aoife says, still with her back turned.
Aoife sighs. "For fuck's sake."
Monica flinches at the phrase. An ugly thing to say, a horrible thing. Joe had said it to her when —
"It's a word that everybody knows," Aoife says. "Except you, it would seem. It begins with s."
There is a pause. They listen to the high chirrup of a bird, the tussling flap of the breeze catching in Monica's hem, the distant pulse of the waves.
"I'm sorry," Monica says, on the track over Omey Island, to her sister's rigid back.
"For everything. For thinking you would ever have told Joe. Of course you never would have done that. I don't know why I forgot that about you. And ... " Monica pauses, tugs at the cuffs of her nightdress. " ... I said some terrible things to you, that day in the kitchen. Awful things. I've regretted them ever since."
"Yes. I should never have lashed out at you like that and I shouldn't have said them and they're not true and — "
"Ah, now I know you're lying."
"What do you mean?"
"Well, they are true, aren't they, those things you said about Mum and me as a baby? I know they are."
"Well." Monica opens her hands and shuts them again. "I should never have said them, either way. The last three years have been horrible without you." Monica sighs, and as she does so she realizes that this is true and that she isn't going back to Gloucestershire: all that is over for her. She will not return to the farmhouse, she will not live there again. Jenny and the children will come back to live at the house that was never, after all, hers. She regards this notion with an odd calm. It is a fact, stolid and uncomplicated by indecision: she is not going back there. "Horrible," she says again.
Aoife turns now, to face her. "Really?"
"I ... I don't seem to make the right decisions when you're not around," Monica says. "Like the dress I wore for my wedding. I bought it the week before, in a panic. I knew the skirt was too short and it made my knees look awful and it just didn't suit me. The woman in the shop told me it looked lovely and so did Mum, and I wanted to believe them. But when I saw the photos, I kept thinking, If Aoife had been around, she would have said, Don't wear that, not that, it looks terrible. You would have sorted it out."
"It was a bad dress."
"Turquoise watered silk, netted skirt, puffed sleeves."
They are walking now, together, back to the cottage, their steps in rhythm. Monica had forgotten that she and Aoife could do this, could walk in perfect unison; she's never found this exact, metronomic motion with anyone else. It must come from all those years of walking together, to school and back, to the shops and back, to the bus stop, the tube, the library.
"It sounds vile."
Aoife stops at the cottage gate. "So you got married dressed as Little Bo Peep?"
Monica laughs. She wants to say to Aoife: That's it, I'm not going back to him, it's over. She knows Aoife will understand, won't ask too much. But there will be time for that later. "I did."
"Ah well." Aoife shrugs. "We all make mistakes."
Monica sighs. She puts a hand out and touches Aoife's arm and Aoife doesn't pull away. "We do," she says.
Excerpted from Instructions For A Heatwave by Maggie O'Farrell. Copyright 2013 by Maggie O'Farrell. Excerpted by permission of Knopf, a division of Random House, Inc. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.