He’d only had that one shot. Now the current was sweeping him away. Mackerel hooked his arm around the line holding Davey’s body and sawed it through with his knife. He released some of his own buoyancy, letting his weight drag him deeper into the trench, away from the surges close to the surface, dragging Davey’s body down with him.

He swam for the tunnel to Tasmans Arch. His escape route.

Then he felt the resistance on the line loosen.

Davey fell past him like a rock, his BC burst and spewing bubbles, disappearing into the kelp, down into the crevasses that made up the floor of the trench. Down there at the bottom the current moved and tumbled in and out of a hundred rocky channels. Davey’s body would get shredded to pieces as it was sucked out into the depths.

Davey . . . no . . .

Mackerel looked up.

The assailant was floating, perhaps three metres away, but not drawing closer.

Mackerel had one thought.

Get him.

He took a full breath to change his buoyancy, sensing the movement of the current, seeing the swirl of the kelp, and again launched himself towards the man, kicking with all his strength.

The assailant turned and swam away. He headed for the entrance to another tunnel, which Mackerel knew would lead him into one of the many systems of sea caves, here in the cliffs. But Mackerel knew those caves intimately; he had practically grown up in them.

But this man clearly knew them as well. And the other man was stronger than Mackerel, faster.

Now Mack sensed something else, a different kind of pressure building behind him. A new twisting shift in the current, one he hadn’t felt before.

A feeling of terror broke through the calm of the bubbles.

The waves crashing against the cliffs were forming a whirlpool.

Mackerel had just forced his arms in through the opening tunnel and wedged himself in a frond of rock when he felt the pull of the whirlpool sucking his legs back out, twisting one of his fins like a broken rudder. Mackerel unlatched it from his foot, before his ankle was broken, and the fin was sucked away into the dark below.

He wedged himself in tighter, forcing himself to stay calm.

Breathe in, bubbles out.

His ears hummed with the change in pressure, silver baitfish and shreds of kelp flying past, the sound of the whirlpool deafening, until finally the current stabilised and Mackerel felt the backwash flowing into the cave. He lunged forward, letting himself be carried along, reaching for the next safe recess in the rock.

He knew this tunnel, and now, the further he got from Devils Kitchen, the weaker the pull of the whirlpool behind him, his diving torch lighting the way through the murky dark. He couldn’t panic – if he panicked, he’d become disoriented and be lost in there for good.