Banni stood wailing on the bank of the river, head thrown back, tears flowing down her cheeks and falling off her chin. Nanda and the boys tried to comfort her, without success. Whenever her wailing turned to words, all that came out of her mouth was, ‘Sister! Sister!’

The rain had eased off and the heat of the sun raised steamy water vapour from every tree and bush. The last of the storm clouds sat on the peaks of the hills that reared almost sheer from the river’s edge. Finches gathered to chatter in the ferns, as if attracted by Banni’s howls.

But Nanda had her eye on a new mass of cloud sweeping in from the east. She urged everyone to shelter under a massive overhanging boulder, and the boys obeyed her, but not Banni, who was crying, ‘Come back, Sister! Come back! All my bangles I give to you!’ This was a serious sacrifice; Banni’s bangles had been her pride and joy, but they’d been left at the house when the soldiers came.

The rain came down with such ferocity that Nanda was able to prevail on Banni to take shelter. But even under the roof of rock, she wept loudly and called on her sister to return. Nanda, who sat stroking Banni’s hand, secretly doubted that Malini could have survived.

Banni seemed to read her mind. ‘She will come back! I promise you.’

Nanda agreed. ‘Of course!’

The rain fell so heavily that it formed a temporary waterfall, curtaining off the entrance to the shelter. Nanda feared a mudslide, or even an avalanche. She had seen it happen in the past: the rain loosened boulders, and the plunging stones knocked others in front of them. Even the boulder she and the children huddled under could be smashed by tumbling rocks. But what was to be done? Until the rain stopped, it was impossible to see more than an arm’s length away. And she had to get the children dry as soon as she could. They were already shivering in their sodden clothes.

Dim though the light was beneath the boulder, Nanda could just make out a natural tunnel that appeared to lead upward in a gradual way. She climbed up to investigate.

The tunnel opened into a broader gallery, and Nanda had to judge whether it was safer for the children to remain where they were, or to risk moving them into the gallery. If a mudslide come down the mountain, it might entomb them, but if rocks came down with the mud, they might all be crushed under the boulder. She decided she would risk the gallery.

First, Nanda had to persuade Banni to retreat into the tunnel.

‘And Malini? What will my sister think when she comes back and finds us gone? No! Here I stay!’

Nanda went out into the pounding rain. Above the bank of the river she made a big arrowhead shape with rocks, pointing towards the boulder. Then she took off her Bon Jovi T-shirt and attached it to a stick driven into the ground, so that it would act as a signal.

Nanda was putting on a show for the children’s sake, trying to appear the very model of bravery and competence. But the truth was that she could barely hold herself together. Malini had come into her life like a blessing, and she adored her. She’d come to think of Malini as her protector. For the first time ever, Nanda had begun to believe that her journey through life might lead to some sort of haven. But now Malini was most likely dead. She was constructing a signal for a person who would never return. The full burden of the life she’d led before the comfort of Malini settled on her heart once more, and she ached in every muscle with grief.

With only her frayed singlet and her shorts to clothe her, she called Banni to look at what she’d done.

‘Do you see?’ she said to Banni. ‘She will know where we are.’

‘You will catch a bad, bad cold,’ said Banni. Then she added, ‘Nanda, I thank you.’

Nanda led the way on her hands and knees. Banni brought up at the rear, urging on the boys in front of her. As Nanda lifted her head to peer into the gallery, a thousand tiny lights came to life. She gasped with astonishment. The boys behind her baulked, not knowing what was happening ahead. Banni bumped into Gayan, and shrieked in Sinhala. ‘Do I want your behind in my face?’ she said. ‘No, I do not!’

‘I am sorry,’ said Gayan. ‘Truly, Banni, miss.’

‘Shush!’ said Nanda.

The lights were – well, what were they?

‘Insects,’ Nanda whispered. ‘Like fireflies.’

Insects they were, luminous insects, but they looked like jewels. In their light, Nanda could just make out the dimensions of the gallery, and it was huge, enormous: ten houses could fit into the cavern. Pillars grew up from the floor and down from the roof, as if a temple had been constructed here by some strange race: built, then abandoned.

‘Oh, children!’ she called. ‘This is magical!’

All alarm forgotten, the boys crawled over each other to reach the gallery.

‘Aiee!’ cried Amal.

And Gayan, his head raised in wonder, clapped his hands together lightly, as if in praise. He said, ‘It is the home of Buddha. Oh, surely!’

Nanda wriggled her way from the tunnel into the gallery. She stood and gazed around. The other children joined her, Amal squeaking with the wonder of it all, Gayan gazing about gravely. The insects could not be seen, only their light, no matter how close they got to them.

Nanda took a cautious step, and another. Then she stopped. On the floor of the gallery lay the remains of a campfire: charred sticks, grey ash. And close by, a backpack and an open metal box full of cartridges. Nanda had seen cartridges like this before. The soldiers without uniforms who had come to the orphanage carried guns that fired rapidly and threw out shells of this sort. Nanda backed away, as if the cartridges were venomous snakes. ‘Don’t touch them!’ she told the boys. ‘Don’t go near them!’ An awful trembling came over her, and a sickness in the pit of her stomach.

The insect lights went out, not slowly but in an instant. Nanda reached out towards the boys and Banni and pulled them to her. They stood huddled close together in the darkness, scarcely breathing.

Amal whispered, ‘Mama, what will we do?’

‘Just stay still,’ said Nanda. ‘Let’s sit.’

They sat still for an hour or more. Gayan, with his knees drawn up, buried his head in his arms and whispered over and over the brief phrase he always repeated in times of dread. ‘I don’t care…I don’t care…I don’t care…’

Amal had his own strategy for dealing with fear – a long, rambling story, also told in whispers, all to do with shooting his enemies and dropping bombs on their houses.

Finally Banni said, ‘I am going back out to look for Sister.’

‘Wait!’ said Nanda.

A faint scraping sound was coming from somewhere within this underground world, right on the edge of hearing.

Banni whispered, ‘What is it?’

‘I don’t know,’ said Nanda.

‘We must run!’ said Banni.

‘No. Don’t speak.’

The boys hugged Nanda more tightly. Whatever was making the sound was moving towards them; with each passing minute, it grew a little louder. Was it a human sound? Nanda thought she could make out grunts of exertion. Gayan whispered, ‘Mama, it frightens me!’

‘Be still,’ said Nanda. ‘Be still and wait.’

A voice came out of the darkness, too: a boy’s voice. What was the boy speaking about? Nanda heard the word ‘elephant’ distinctly, and ‘birthday cake’. What in the world?

‘…it was her birthday, you see…I have baked you a beautiful…lady elephant…Ha ha ha!’

Banni whispered, ‘What is happening? Who is speaking?’

‘I don’t know,’ said Nanda.