And for both of them, it was the shock of cold when they leapt in. It was even more intense than Damien expected, heart-thumpingly brisk. There was nothing you could do to prepare yourself for cold water. Pushing off from the rock ledge, they made for the island and the cave that yawned darkly on one side.

‘The cave’s where the treasure is!’ said Max, putting his head down to plough forward. He swam with choppy strokes and Damien followed, then overtook. He kept being shunted off course, and it was only after a third readjustment that he realised how powerful the current was. As they neared the cave he felt himself being sucked towards the deep opening in the rock – he figured the cave must run all the way through to the other side of the island. Swimming through it would be a worthy challenge, an adventure in lieu of the surf they’d missed.

But when he turned to check where Max was he knew they could not go on. His cousin was struggling – no, flailing. His face had a glazed expression. Damien could see he was about to start panicking.

‘Abort!’ he called out. The wind tossed his words away. He knew they had to move, and fast. If Max went into a full-blown freak-out, he’d be impossible to help. He was bigger than Damien, tall and broad-chested, and a panicking man was dangerous. Damien knew stories of ocean rescues gone wrong, when the person in trouble drowned his would-be rescuer. It was a primal response to flail about or fight.

Damien drew a finger across his neck in a cutting movement. ‘Abort!’ he yelled again. ‘We’re going back!’ And without waiting he started swimming to shore, giving Max no choice but to follow.

This was at a time in Damien’s life when he lived for surf trips, saving everything he earned so he could spend it chasing waves. Missing the surf that afternoon had made him push their luck, or at least blinded him to the risks of swimming to the cave. At some level he imagined the ocean owed him something – a different thrill in recompense.

Of course, he never imagined Max would get into trouble. Damien knew he was by far the better surfer, but he hadn’t questioned – should he have? – his cousin’s ocean fitness. In Wollongong, where Damien grew up, you either surfed or skated; those were the only options on offer. Having surfed his entire life, he was used to being in the ocean. It took a lot to spook him.