She didn’t reply, but a grimace of uncertainty crossed her face, as if she’d lost confidence in her ability to do anything but keep swimming forward. Prabir measured the depth with one glance; there was no point even trying to stand. He couldn’t just snatch her and wade back to the shore, ignoring her screams, her pummelling and her hair-pulling.

He swam beside her, trying to shepherd her into an arc, but he was far more wary of colliding than she was. Maybe if he just grabbed her and spun her round, making a game of it, she wouldn’t be upset. He trod water and reached towards her, smiling. She made a whimpering noise, as if he’d threatened her.

‘Sssh. I’m sorry.’ Belatedly, Prabir understood; he felt exactly the same when he was walking on a log over a stream or a patch of swampy ground, and his father or mother grew impatient and reached back to grab him. Nothing could be more off-putting. But he only ever froze in the first place when someone was watching him, hurrying him along. Alone, he could do anything — casually, absent-mindedly — even reversing high above the ground. Madhusree knew she had to turn back, but the manoeuvre was too daunting to think about.

Prabir cried out excitedly, ‘Look! Out on the reef! It’s a water man!’

Madhusree followed his gaze uncertainly.

‘Straight ahead. Where the waves are breaking.’ Prabir pictured a figure rising from the surf, stealing water from each collapsing crest. ‘That’s just his head and shoulders, but the rest will come soon. Look, his arms are breaking free!’ Prabir imagined dripping, translucent limbs rising from the water, fists clenched tight. He whispered, ‘I’ve seen this one before, from the beach. I stole one of his shells. I thought I’d got away with it … but you know what they’re like. If you take something from them, they always find you.’

Madhusree looked puzzled. Prabir explained, ‘I can’t give it back. I don’t have it with me, it’s in my hut.’