The pressure-cool expanse of everything that drives our blue planet. The loud rush of bubbles, the hiss of the regulator, the clicks of the water. The ever-rolling movement of ocean and light. He felt the push against his fins, the pull of the weight pouches built in to his BC. He was expert at modulating his buoyancy, using the BC vest or even just by breathing in and out.

He dived deeper through a sway of brown bull kelp, away from the turmoil of the surface. He heard the thud of Ahab’s motor above, powering away, back to safety.

Now Mackerel really was alone. It was stupid to dive without a partner, but Mackerel wasn’t afraid.

Once he got to Davey, his escape plan was a wide underwater tunnel that moved through into the base of Tasmans Arch, which had a shallow shelf where Mackerel could wait and be winched to safety.

It was not a pretty plan, but it was the best he could come up with in a hurry. On land, it had seemed barely possible. But here, under the water, it seemed perfectly sane.

He swam forward, through another curtain of the giant kelp and past the crag that signalled the opening of Devils Kitchen, a flurry of opal-coloured parrot fish swimming the other way. The suction from the ocean was less the further he descended, but the sound above was still ferocious, the water slamming and thundering against rocks.

Breathe in, bubbles out.

He powered on his diving light, angling through the slanting bubble foam and torn shreds of floating seaweed.

Then he saw it.

A diving rope, lined with reflector strips. It ran from an opening in the kelp-lined wall that signified one of the many submarine tunnels, right up to the surface of the Kitchen.

He pulled the rope, trying to haul it towards himself. The current spun him around – without something to brace himself on, he didn’t have a hope.

He swam for where the line reached the cave and set himself inside, bracing his fins on the rock, then began to reel it in.

It was tough work, the rope fighting his pulling. He dragged it towards the cave entrance, focusing on calm breaths, his arms straining against the resistance of the water, releasing air from his BC to compensate.

The sea shifted and danced, silt and sand stirred up by the wind. Through the haze he saw something approaching him, tied to the end of the rope.

It was someone. A person.

He yanked again.

Closer now . . . a glint of gold. A tiger-stripe pattern.

It was Davey!

He wasn’t moving. His tattooed arm was limp.

It was Davey’s body.

Davey was dead.

Breathe in . . . just breathe in . . . no, no, no, please, God, don’t take my brother away . . .