Prologue

For the first twelve days of our life, we were one person. Our father’s brains and our mother’s beauty swirled into one blessed embryo, the sole heir to the Carmichael fortune.

On the thirteenth day, we split. It was almost too late. One more day and the split would have been incomplete. Summer and I would have been conjoined twins, perhaps sharing major organs, facing a choice between a lifetime shackled together and a surgical separation that might have left us maimed.

As it was, our rupture was imperfect. We might look identical, more than most twins, but we’re mirror twins, mirror images of each other. The minute asymmetries in my sister’s face— her fuller right cheek, her higher right cheekbone— are reproduced in my face on the left side. Other people can’t see the difference, but when I look in the mirror, I don’t see myself. I see Summer.

When we were six years old, Dad took a sabbatical from Carmichael Brothers, and our family sailed up the east coast of Australia and into Southeast Asia. Our home town, Wakefield, is the last safe place to swim before you enter croc territory, so Summer and I and our younger brother, Ben, spent a lot of time on that cruise playing inside our yacht.

I loved everything about Bathsheba. She was a custom- built sloop, her sleek aluminum hull fitted out with the best timbers— teak decks, oak cabinetry— but what I loved most of all was the ingenious double mirror in the bathroom. The builder had set two mirrors into a corner at right angles, with such care that I could scarcely discern the line of intersection. When I looked squarely at either one of these mirrors, I saw Summer, as usual. But when I stared between them, past that line, into the corner, I saw a nonreversed image. I saw my true self.

“When I grow up, I’m going to have one of these mirrors in my house,” I told Summer, watching the solemn blond girl in the mirror mouth the words in time with my voice.

Summer put her little hand on my chest. “But, Iris, I thought you liked pretending to be the right— the other— way round,” she said.

“Mirrors don’t change what’s on the inside.” I pushed her hand away. “Besides, my heart is on the right side.”

We were the most extreme case of mirroring the doctors had ever seen. It wasn’t the facial differences, barely detectable without calipers. They had scanned my abdomen when I was a baby, and my liver, pancreas, spleen, all my organs, were on the wrong side of my body. This was how the doctors knew that we had split so late. When I lay still and watched my bare chest, it was the right- hand side that rose and fell in a rhythmic flutter, proof that my heart was misplaced.

Inside Summer, though, everything was as it should be. Summer was perfect.

PART I: Iris

1: The Mirror

I wake in my twin sister’s bed. My face is squashed between plump pillows covered in white cotton. It makes me feel like a kid again, swapping places with Summer, and yet everything has changed. We’re adults now, and this is Adam’s bed, too.

I roll over and survey the marital bedroom. Everything is oversize and lush; the colors are creamy and airy, but the carpet is the color of a ripe peach. There’s something illicit about lying here, even though Summer and Adam are thousands of miles away, not even in Australia anymore. Someone must have changed the sheets since they left, but I can smell Summer. She smells of innocent things: suntan lotion, apples, the beach.

This room breathes Summer, so it’s jarring to remember that she didn’t choose these furnishings. Adam owned this house when Summer married him, not long after his first wife, Helen, died. The room looks much the same as it did on Summer’s wedding day. It’s just like my sister to mold herself into the life that another woman left behind. She’s easygoing to a fault.

The super- king bed is nestled into a bay window with decadent views of Wakefield Beach. I struggle to sit up— this bed is too soft— and lean against the mahogany headboard, bathing my face in the light of the rising sun. The Coral Sea’s turquoise mingles with gold shards of reflected sunbeams. I wish I were in the water right now, swimming in those colors. There are a few things I need to wash off.

From here, perched on the cliff edge, in one direction I can see Wakefield River, north of the town, cutting through the land like a wound. Summer has always loved the river, although, as a breeding ground for saltwater crocs, it’s not swimmable. She likes to look at it from the safety of the bridge that our father built across it— his first construction project.

In the other direction, a faultless beach sweeps north to south, wild and open to ocean waves. Halfway along the beachfront, one mansion, faux Victorian with a hint of Byzantium, dwarfs the other beachfront dwellings. It’s the house we grew up in; at least, that was where we lived until Dad died.

My mother, Annabeth, must still be asleep in the spare room, so this is my chance to check out Summer’s loot. If I were house- sitting, I wouldn’t cram myself into the guest bedroom, but Annabeth revels in being unassuming. She tried to stop me sleeping here when I turned up late last night, but I couldn’t resist.

I claw my way out of the heaped bedding and rub my bare feet into the thick carpet. March is still high summer in Wakefield, and as I pad around the room, the warm air kisses my naked body. This time yesterday, I was in the mountains in New Zealand, where winter was already frosting the morning air.

One wall of the walk- in closet is lined with Summer’s dresses, a rainbow of silk and lace. I’m surprised that her drawers are still full of lingerie, even though she and Adam plan to be overseas for a year. The lingerie is typical Summer stuff, overrun with roses, demurely styled, more suited to a preteen girl than a married woman of twenty- three. There are loads of it; she surely wouldn’t notice if half of it disappeared— not that I would dream of stealing. I suppose she couldn’t fit all her clothes on the yacht.

The yacht. Bathsheba. This is the nub of the thing. This is why I feel as though Summer and I have swapped places. Because Summer’s on Bathsheba. And Bathsheba’s not mine, she never was mine, she never will be mine, but I feel that she ought to be. It feels as though Summer is sleeping in my bed, on my yacht.

Summer never loved Bathsheba, but now Bathsheba is her home. She and Adam have bought the yacht, bought her fair and square from Dad’s estate, and now Summer and Adam own her as much as they own the house that I’m standing in right now.

What do I own? A shrinking bank account, a wedding ring I don’t want anymore, a bunch of furniture I’ve left behind in New Zealand. A piano I’ll probably never play again. It was a cheap instrument, anyway. Summer and Adam have a better one.

I pick up a bra- and- knicker set that’s so innocent it’s almost porno. Yellow gingham, it reeks of boarding school: hockey sticks and cold baths. The bra is a double D, and I wear a D, but it looks like it’ll fit. I step into the panties. I want to see what Summer looks like in these.

As I’m fastening the bra, the phone rings in a distant part of the house. That’ll wake Annabeth. I suppose I will have to face up to her and her questions about why I’m here. I pretended to be too tired last night.

I barely have time to think before Annabeth bursts in on me.

“Here she is,” my mother says into the handset as she minces across the bedroom in a frumpy nightie, her blond hair looking frizzy and streaked with gray. My mother is at the age where she needs makeup and hair products to achieve the beauty she once woke up with; she’s not looking her best right now. “No, no, she was already awake. Love the gingham bra, Iris. Summer has one the same.” Her sleepy blue eyes peer at me myopically. She dangles the receiver in my face as though I won’t be able to see it unless it’s right under my nose.

I grab the phone and shoo Annabeth out of the room. “Close the door behind you!” I call. Who could be phoning me?

Who even knows I’m back in Australia, let alone in my sister’s house?

“Hello?” My voice is craven, as though I’ve been caught somewhere I shouldn’t be.

“Iris! Thank goodness you’re there.” It’s Summer. Her voice breaks into jagged sobs. “You have to help me. We’re in trouble. You’re the only one who can help.”

I can’t quite focus, because I’m wondering whether Annabeth’s comment about the bra gave the game away. Summer can be oddly territorial about her clothes. But my sister doesn’t seem to have heard. She’s saying something about Adam, something about how she needs me, Adam needs me. Adam wants her to say that it was his idea and he’s praying I’ll accept.

I gaze at a rack of Adam’s white business shirts. Each one holds Adam’s shape as though a row of invisible Adams is wearing them, here in the closet with me. The shirts are so big in the chest, so long in the sleeve. I hold one to my face. It smells of cloves. I can see Adam in this pristine white, his skin glowing darkly.

“The poor little man, his pee- pee is swollen and red, and there’s something seeping out. It’s horrific. The foreskin is so stretched. He’s crying all the time.”

What is she saying? I’m agog. We’re twins, but we don’t have that kind of relationship. I’ve never heard Summer describe anyone’s penis before, let alone her husband’s. What the hell is wrong with him?

“The worst part is when he gets an erection. It’s excruciating. Babies do get erections, you know. It’s nothing sexual.”

Babies?

“Wait,” I say. “Are you talking about Tarquin?”

“Who else could I be talking about?”

Silence.

Tarquin. The other thing that Summer took over when Helen died, along with Helen’s house and Helen’s husband. The baby.

Summer is Tarquin’s mother now. Adam and Summer agreed that Tarquin deserved a normal family, so Tarquin calls Summer “Mummy.” Or at least he will if the kid ever learns to speak.

“Summer, I know baby boys get erections,” I say. “We have a younger brother, you know. I’ve seen these things.” Summer always assumes I know nothing about kids, explaining that they need a daily bath and a regular bedtime, or something equally fascinating, like I’m an idiot. The last thing I want to think about is Tarquin’s pee- pee, especially if it’s seeping.

“Trust me, you’ve never seen anything like this,” Summer says. “It’s becoming dangerous. The infection could spread. The doctors said he could lose his penis. He could die.” The word comes out with a sob. “He needs surgery. An emergency circumcision. They can’t fly him home. He’s having the surgery today, here in Phuket. We’re at the international hospital.”

Summer’s voice is fast and fluttery. She’s teetering on a tightrope between shouty hysteria and a flood of tears. Most of the time, Summer is the self- assured, gracious twin, while I’m nervous and gauche, but when the chips are down, I’m the one who keeps her head.

I step up to my role now. I hang Adam’s shirt back on the rack and smooth it into place. No one could tell it’s been touched. “An international hospital sounds good,” I say.

“Yes,” she says. “They’ve been so kind to us here.”

“That’s good, and it’s good that you’ve rung me,” I reply. I say “good” like it’s a mantra, calming Summer. “Of course I can help. So you haven’t told Annabeth yet?”

“I couldn’t . . .” Summer’s voice quavers again.

“I can tell her. She can fly up to Phuket today. I don’t mind taking over the house- sitting for a few days.”

No response.

“For as long as you and Adam need it,” I add generously.

“No, no, Iris, we need you, not Mum.”

My head buzzes. Summer needs me. Adam needs me. But why? I’m no good with babies. Tarquin already has both his parents. The only parents he knows, anyway. What do they need me for?

I picture myself in Thailand, swanning around the Royal Phuket Marina with its flotilla of superyachts, drinking cocktails. Strong ones, not the virgin cocktails Dad bought us when we were kids. Surely not all those millionaire yachties want Thai girlfriends. Some of them must prefer blondes.

But what am I thinking? Tarquin is ill. It sounds like his penis is rotting off. There’ll be no time for drinking and flirting. Surely.

“We’re in a serious bind, Iris, and we can’t tell just anybody about it. Only people we trust one hundred percent.” Summer pauses.

“Well, obviously you can tell me,” I say.

“Of course,” says Summer. “I’m just saying, you must keep this a secret. The thing is, our import permit for Bathsheba has expired. We’ve already checked her out of Thailand. We were ready to go, but the beaches are so beautiful here. We thought we could spend another couple of weeks in a quiet anchorage and no one would know. We never imagined Tarquin would get sick. It’s terrible timing. If customs find Bathsheba’s still in Thailand, they’ll seize her.

The people here are lovely, but there’s so much corruption.”

Summer makes it sound as though corruption is some affliction, like malaria, that the poor Thais suffer through no fault of their own. But I’m too keen to hear more to quibble with her.

“So what do you want me to do?”

“Oh, Twinnie, I don’t know how to ask you such a huge favor. Adam’s a good sailor, but he’s barely been out of sight of land. You know how hard it is on the open sea. It’s a long passage to the Seychelles, at least a fortnight, and the end of the season is near. The typhoons start in April, but we can’t wait till April anyway. We need to get Bathsheba out of Thailand now. And you were always such a great sailor, Iris. We’ll pay your plane fares, of course, and Adam says you can stand whichever watches you want.”

As Summer speaks, I step back into her bedroom and approach the bay window. The water glitters far below, swirling around sun- bleached rocks. I can’t let myself believe Summer’s words. They’re too good to be true. I’ve melted through the glass, and I’m flying over the ocean, turning a joyous shade of aquamarine.

Adam’s speaking in the background now. Has he been listening all along? “Tell her I’ll do all the night watches,” he says, in that deep voice flecked with the cadence of the Seychelles. His voice goes on more quietly. I hold the phone close to my ear and shut my eyes, straining to hear.

“Believe it or not, Iris likes sailing at night,” Summer says. When she speaks to Adam, her voice becomes playful, smooth, liquid. No wonder I can barely stand to be in the same room as my sister and her husband.

But it seems I wouldn’t have to spend much time with the two of them. The plan seems to be that Summer will stay in Phuket with Tarquin and his festering genitalia, and I will leave behind my failed job, failed marriage, and failed life, and sail across the Indian Ocean on the yacht I have loved since childhood. And who will go with me? My brother- in- law, the wealthy, handsome, charismatic Adam Romain.

I imagine sailing into the Seychelles, a dream country of coconut palms and halcyon beaches, but I’m not a mere tourist, because my husband is a local, so in a way, it’s a homecoming.

Well, not husband in my case. Brother-in-law. But still.

“Of course I want to help,” I say, “but I have a lot of job interviews lined up.” This isn’t true; I haven’t started looking yet. I’ve been trying to figure out how to explain to prospective employers why I walked out on my last job. “And I have a lot of bills.”

Summer’s voice when it comes back is quieter. “We’ll cover everything,” she says. “Plane fares, debts you need paid, anything you need. I’m sorry, Iris. I know things have been hard for you with Noah leaving. I know it isn’t fair to ask. If I wasn’t desperate. If we weren’t desperate . . .”

It’s not often that Summer’s in need. All our life, she’s been content with what she has, happy with her lot. As anyone would be who had Summer’s lot. But I can’t bear to stretch it out. She sounds truly unhappy— and in a moment, she might think of someone else to ask.

“I’ll do it,” I say. “I’ll do it for you, Twinnie.”

Summer squeals down the phone.

In a few minutes, everything is planned. Adam has found a direct flight on his smartphone. I’ll leave Wakefield this morning. I have an hour to pack and to tell our mother before I head to the airport. I’ll be in Phuket by this evening. I’ll be on Bathsheba.

Adam comes on the line. “What’s your date of birth? Oh, stupid me, of course I know that. What’s your middle name? Same as Summer’s?”

“No middle name.”

“Really, just Iris? Okay, that’s easy. Short and sweet. Hang on a second, hon— Iris— the website’s confirming the booking.”

Did he almost call me “honey”? The thought has a deep effect on me. I feel it in my body. I flush with shame; I really should get out of Summer’s underwear.

But now Adam’s saying goodbye. In the background, Summer is asking about Tarquin’s vaccinations, but Adam doesn’t know the answers to her questions. He’s always so vague, it makes me wonder how the hell he manages to run a travel agency. Summer has to handle all their life admin. He hands the phone back to her, and she asks me to email Tarquin’s vaccination records to her. Then she hangs up.

Finding the records is easy. Summer has filed them all in the closet. I’m struck by her extreme organization. Her life is laid out here in writing; there’s even a folder labeled adam’s favorite meals. When I pull it off the shelf, a sex manual falls out. The Millennial Kama Sutra. It looks well worn.

I could browse all day, but I have to get moving. I have to dress, eat something, tell Annabeth the plan. My mother’s barely gotten her head around my sudden appearance, and now I’m disappearing again. She’ll freak out about Tarquin, too. She treats the kid like he’s her blood grandson.

First, I dart into the en suite bathroom for one glimpse of Summer in her good- girl gingham. And that’s when I see it. The one thing that Summer has changed about this house.

The two panes of glass must have cost a fortune, and it must have been quite an operation to hoist them up here. They seem larger than the door. They’ve been installed with great care. The angle is exact, the seam almost invisible. Even better than the one on the yacht.

It wouldn’t bother me, it wouldn’t gnaw at my insides, if Summer had genuinely wanted a double mirror. We are twins; I can’t blame her for wanting the same things as I do. But Summer has never minded who she sees in the mirror. She’s never been interested in the “mirror twins” thing. I can see she has installed this mirror because it looks good. It fits into the space beautifully, and with the door to the bedroom open, it reflects the bay window and the ocean beyond.

Even the things Summer doesn’t care about she gets first.

I stare diagonally into the double mirror. The girl in the mirror stares back. She’s wearing Summer’s yellow underwear, but she isn’t Summer. It’s her left cheek that’s fuller, her left cheekbone that’s higher.

The girl in the mirror is me.