Bali, July The air smelt of clove cigarettes, fried fish and motorbike fumes. Westerners filled the pavements and were courted by the Balinese with their winning smiles. Katie wove through the crowd beneath the solid weight of her backpack as the traffic flowed past, taxis shunting and beeping with beads and flowers jiggling from rear-view mirrors.

She paused for a moment in the shade of a doorway while she checked the map: the hostel looked near, two streets away now. She had asked the taxi driver to drop her short of the hostel the stop-start traffic had made her queasy and the back windows hadn't opened but now she regretted the decision as weariness spread through her body like the heat.

She tucked the map away and lifted the base of the backpack with her hands to allow her shoulders a moment's respite from the pinch of the straps. Then she pushed on, squeezing through a group of noisy tourists haggling over silver jewellery. She turned right and then immediately left, which carried her down a narrow road flanked by bloated rubbish bags.

The Nyang Palace was announced in faded yellow letters painted across a piece of hardboard. The sign was propped on a plastic chair beside a doorway. She moved into the dim entrance, stepping over a woven basket filled with wilting orange flowers and grains of rice.

Inside, the smell of cooking oil hung thickly in the air. A group of travellers lingered around a tired settee, speaking in a language Katie couldn't place. Behind the reception desk a heavy woman sat on a stool eating rice with her fingers. Beyond her, a man wearing a pair of dark glasses was stretched out on a mattress, watching television.

'Hello,' the woman said, sucking her fingers clean. 'You want room?'

'Yes, please.' Katie kept her backpack on, hoping the transaction would be swift: she wasn't sure she'd find the energy to pick it up again.

'Dorm room? Single room? Double room?'

'Single, please.'

'Fifteen dollar.'

Katie had changed half her money into rupiah at the airport, having been advised to pay in Balinese as the deals were better. 'In rupiah, please?'

'No. No. Dollar only. Dollar.'

She handed over $15, too tired to haggle.

The woman shuffled out from behind her desk; she was wearing bejewelled sandals, her toenails polished a deep, glossy violet. Katie glanced at her thick hands and bitten, ridged fingernails and wondered what small pleasure she must take in dressing her feet so particularly.

She was led up a set of stairs and along a corridor where paint peeled from cracked walls. The woman unlocked a door and then handed the key to Katie on a knotted piece of greying string.

The orientation of the hostel was brief: 'Toilet,' she said, pointing to a green door with no visible handle. Then she indicated towards the ceiling, saying, 'Terrace for smoking up there. No smoking in room.' The heels of her sandals made sharp clicks along the corridor as she left.

The room was dingy, cast into shade by lank brown curtains that were fraying at the base. She tugged them open, disturbing a mosquito that buzzed groggily to the ceiling. The view through the streaked glass was of the dilapidated building opposite, a slice of early-evening sun visible above it. She shrugged off her backpack and sank onto the bed, trying not to think of how many other people had slept on the thinning mattress.

In the quiet heat of the room, she realized that each of the places she had visited over these past few months had been leading her here: Mia's final stop.

She unbuckled the backpack and pulled out the journal. Flicking her thumb through the leaves, she guessed there could be no more than sixty pages remaining: few enough to read in one sitting. She could do it right now, tear through them in a matter of hours. It was all here beneath her fingertips, waiting for her to begin turning the pages.

But she knew she couldn't read it like that, not all in one go. Not yet. For months she had been making this journey alongside Mia, coming to understand her sister through her own words. If she read these final pages now, then it would be over. She'd have to leave Mia, for good.

She put the journal away, deciding that she wouldn't read any more until morning. Tonight there was only one thing that she needed to do, something she'd already put off for far too long.

She smoothed her hair behind her ears, picked up her bag and left the room.

Her mobile had no reception, so she found a payphone two streets away. It was near a lively bar where travellers laughed and drank in groups like packs of animals drawn to a watering hole. Music drifted down the street, catching a young couple in its rhythm. The girl's hips began to sway beneath her sarong and the boy made a jazzy shuffle step in his flip-flops, causing the girl to laugh. They clasped hands, interlocking their fingers so the hearts of their palms were touching.

As she turned back to the payphone, Katie hesitated. Is this the phone you used, Mia, when you called me the day before you died? Were you nervous about ringing to ask for money? Or didn't you give it a second thought, knowing how readily I always said yes to you? I can still hear every word of that conversation the last one we'll ever have and it haunts me. What I said to you will always haunt me.

She took a deep breath, then dialled Finn's parents to ask them for his current number. She hoped his father would answer; if it were his mother there would be too many questions. She cleared her throat and held the phone to her ear.

'Yes, hello?'

His voice was a shock and sent heat flooding to her cheeks. 'Finn?'

A pause, then, 'Who is this?'

She heard the unmistakable note of hope in his voice. The foreign dialling tone, the slight delay on the line, her voice sounding so similar to her sister's. Had he allowed a small part of himself to imagine it could be Mia?

'It's Katie.'

She caught the disappointment lodged in his sigh. 'Katie.'

Would it always be this way, reading into his sighs and tones and pauses, wondering if the man she loved had loved her sister more? She pressed her lips together, allowing herself a moment to compose herself.

'Katie,' he said again, brighter this time. 'I'm pleased you've called.'

'I didn't expect you to answer. I was ringing your parents to ask for your number.'

'I'm staying in Cornwall for a while.'

'Oh. I see,' she said, surprised he wasn't back in London. 'What are you doing there?'

'Working at the Smugglers' Inn again. I've been promoted to pulling pints.'

She smiled. It was the village pub near the harbour where Finn had collected glasses and wiped tables during his A levels. 'Pulling pints? It's a big jump. Are you sure you're ready for it?'

'The empty tips jar suggests not.'

'Is it still the same regulars?'

'Mostly. They all ask after you. Spinney Jackson wanted your address so he could write.'

'That's kind.'

'I didn't know what to tell him.' There was a pause. 'Where are you, Katie?'

She fiddled with the zip on her bag, tugging it backwards and forwards with one hand. 'Bali.'

'Bali? You're actually there? I've heard about what you're doing following Mia's travel journal.'

'Have you?'

'I was in London a couple of months ago and tried to get in touch. You've changed numbers?'

'Yes, a while back.'

'I was worried. I went to your office.'

He was worried about me? She felt absurdly pleased by the image of Finn asking for her at the office. He'd been there once before to meet her for lunch, and he'd chatted to the security guard by the front desk while she reapplied her lipstick in the reflection of her computer screen before going out to meet him.

'A colleague said you'd quit and gave me Jess's number. She told me the rest.'

Katie had forgotten how well Finn and Jess used to get on. She liked the image of them talking together. 'I'm sorry. I should have told you myself. I left in such a rush, I don't think I even believed I was going until I found myself on a plane.'

'I didn't know Katie Greene did planes.'

'Neither did she.'

'Ed been out to meet you?'

'He came to Australia.' She hesitated, pressing her lips together. 'Actually, we've split up. I found out about him and Mia.'

'Oh...'

'Mia talked to you about it, didn't she?'

'Yes, just once.' He sighed. 'I'm so sorry. You've been through hell.'

'Hasn't been my best year.'

'How are you feeling? Really?'

She considered the question. At first, she'd been crushed by her break-up with Ed. But now, she no longer felt the sharp ache in her chest when she thought of him. In fact, as the weeks passed, she had begun to feel a strange sense of relief. 'I think I'm okay. Perhaps Mia did me a favour.'

'What do you mean?'

'Ed and I, we weren't right for each other,' she told him openly. 'What happened forced me to see that.'

'So it was a sort of shock-therapy-type favour?'

She smiled. 'Exactly.'

'Now you're out in Bali alone?'

A moped fired down the street and she breathed in the tang of its fumes. 'Yes.'

'You're being careful? Looking after yourself?'

'Yes.'

'How are you finding travelling?'

'Tough. Lonely. Exhilarating.' She had an urge to tell him how much she missed him, but she stopped herself. Instead, she said, 'It's been interesting going to the same places as you and Mia.'

'What did you think of Western Australia?'

'Beautiful. Barren, of course, but still incredibly beautiful. The space is overwhelming. On the bus we'd drive for hours without passing another vehicle. It was eerie, almost.'

'And what about Bali?'

She looked up. The night was closing in and she felt a low stir of anxiety. Perhaps for her, Bali would always be a map of Mia's last few weeks. 'I'm not sure yet,' she told him. She smoothed her hair with her free hand. 'Anyway, tell me about you. How have you been?'

'Truthfully? Not great. Some days I still can't believe she's gone. I walk down to Porthcray and imagine that any moment she's gonna come running up behind me.'

She thought of the surreal March day they'd buried Mia, remembering the biting wind twisting beneath her coat as she'd stood outside the church. She pictured Finn in his navy suit, his face tanned, but drawn.

The phone line began to crackle. 'Listen, Finn, my connection is going bad. I rang because I wanted to explain something...'

'Go on.'

There was so much she needed to say but she wasn't sure where to begin. 'Mia's journal it's helped me understand some things.'

'What?'

'I know why she went to Bali now.' She paused. 'You didn't leave her.'

'No. She left me.'

'I never gave you the chance to explain. I'm so sorry for what happened at the funeral-'

'There's nothing to apologize for,' he said firmly, the lightness in his tone vanishing. 'Mia was my responsibility. I should have told you that she was in Bali.'

'No, Finn-'

'She should never have gone there alone.'

'It wasn't your fault.'

His voice was flat, toneless. 'Wasn't it?'

The line buzzed with static and cut out.

Katie searched out a quiet restaurant where she ordered noodles and sat with her elbows propped on the table, watching them grow cold. Occasionally, she tossed them with her fork and they squirmed, shiny and bloated.

Finn filled her thoughts, warm memories from their past planted like kisses: the light popping of soap bubbles on her fingers as they kissed for the first time; the sound of his humming as he cooked; the touch of his lips against her forehead when he left her sleeping in his bed. But then other images barged forwards: Mia's body poised above Finn's as they made love on the rocks; the grins on their faces as they hugged in the red dust while parachutes bloomed above them in the sky; the swing of Mia's hair as she turned and saw Finn at Perth Airport, waiting for her.

A waiter approached her table in tired black shoes that had been polished thin. Glancing at her plate, he asked, 'Everything okay for you, madam?'

Not wanting to cause offence, she swallowed several mouthfuls, the strong spices sticking in her throat, then paid and left.

She walked with confident, purposeful strides as she always reminded herself to do in London after dark. As she reached the entrance to the hostel, she passed an old man with milky blue eyes dragging a cart by a rope tied around his waist. His shoulders were hunched and he shuffled forwards with short, wheezy steps. The cart, lit by two lanterns, was stacked with treasures made from shells: polished clam bowls, shell-fringed mirrors, pearlescent candle holders, wind chimes dripping with conch and tusk shells.

A necklace caught her eye and she paused. Hundreds of tiny white shells had been pierced and threaded together on a loop of string. In the centre of it was a single pearl. Hairs rose on the back of her neck: it was almost identical to the necklace Mia had been wearing when she died. Did you stand here, like me? Did the necklace remind you of the hours we spent together searching Cornish beaches for shells? Was Noah with you? Were you happy then?

She paid for the necklace and fastened it at her throat. The shells were cool against her skin and she pressed her fingers gently to the pearl, warming it.