‘No.’ Forest walked away, feet sloshing in the waves, until he was completely out of earshot, the rumble of the waves masking the sounds between them. He motioned for Mack to stop looking at him – to look out over the waves.

Mack focused on the horizon.

He thought of a secret. One from the heart. It took him a while to even gather the strength to say it to a shell, but he spoke it clearly.

‘Neither of my parents ever told me that they love me.’

He turned back to Forest and the boy approached, taking the shell from Mackerel and holding it to his ear.

He closed his eyes.

‘The shell says . . . it’s certain your mum and dad love you.’

Mackerel’s mouth dropped open, and now cold sweat broke out all over his body.

No, no, no . . . I’m going crazy.

Now he remembered where he’d heard about shell-speaking before. Mad Aunt Miriam.

In her ice-induced psychosis, Ahab’s mother had talked to shells as well. Had it been psychosis?

Forest slipped the shell into his pocket.

‘How?’ choked Mackerel.

The boy shrugged. ‘I told you. Sometimes, the shells speak to me. And . . . there are other things I can do.’

‘Like what? Show me!’ said Mackerel.

‘First, take me to the dive centre. The one with the aquarium.’ He bent down to the sand, picking up three more shells and putting them in his pockets. He held his hand in the water, then stood up. He turned to Mackerel. ‘I want to get close to the fish.’

Overeem’s Dive Centre was a large complex of concrete and wide glass windows, built near the ocean’s edge but backing onto scrub. The place was something like a public square for Shacktown, with an open and airy entrance hall, home to a café, and today there were temporary market stalls set up on the wide tiled area out the front.

The main attraction was the aquarium, one of the biggest in Australia, rivalling Sydney’s and Melbourne’s, but there was also a deep saltwater pool where diving and snorkel classes could run. The dive centre had been one of the first big things that brought the tourists to Shacktown.

Sitting in his car, Mackerel realised that the market stalls meant today must have been Saturday – he’d lost track of the week. There were journalists circling like sharks, filming stories or speaking to the bustling locals.

I can’t handle the media on top of everything else, he thought woefully.

He reached into the back seat and found a baseball cap and a large hoodie. ‘Put these on?’ he said to Forest.

The hoodie was way too big for him – it was like a dress – so Forest bunched up the sides and tied a knot, then rolled back the sleeves.

‘Trendy,’ he said with a straight face.

The shells spoke to him . . .

‘Sunnies?’ said Mackerel, giving him an old pair from his glovebox.