He had a rush of memory, of diving this exact place with Davey. Spear-hunting fish, the comfort of each other under the sea, sharing their kills on a smoky driftwood fire under a brilliant Milky Way sky . . .

His brother was dead. No matter what good Mackerel did now, no matter how he tried to change his life, he would never have those moments with his brother again. He’d fucked that up, hadn’t he? Like he fucked everything up. Now his brother would never be able to say he forgave him. His brother would never be able to tell him he loved him.

Suddenly he sensed a strange shift in the pressure. Mackerel’s instinct kicked in. Something had been in the tunnel behind him. Now it was coming for him.

He dodged just in time to see a hand dart past him, a diving blade glinting in its grasp.

Mackerel spun and twisted, pushing himself away from the cave entrance as hard as he could. He used slimy yellow kelp as a handhold as the swell moved in and around him, his vision obscured by seaweed and silt, light and foam.

He caught a glimpse of Davey’s body shooting back to the boiling surface, the line still holding him in place.

The figure from the cave followed him, mirroring Mackerel’s movements, but then paused. The man’s diving mask was tinted – Mack couldn’t see his face.

Mackerel pulled out his own diving knife. He wanted to see this man’s face before he killed him. Because surely he was the one responsible for Davey’s death, putting his body on display. He would be willing to kill Mackerel to keep his identity secret. It’d be a fight to the death.

So why wasn’t the man moving?

Breathe in, bubbles out.

The man’s face tilted, glancing up at Davey’s body, then back at Mackerel. He held out his knife to signal his aggression.

Underwater you could make no demands, couldn’t curse or threaten. This was just hunting. This was fishing.

Mackerel considered the knife in his own hand. If he could dislodge the assailant’s mask, he’d have the upper hand – it was hard to see underwater without a mask.

It’d be easier to aim for the man’s breather, but he didn’t want him dead and drowned. He wanted answers.

Mackerel felt water gathering behind him, a surge. He sensed the pressure as it approached and released his grip on the kelp, letting the water propel him towards his assailant.

The man, rather than bringing his own knife to parry, tried to twist away.

But Mackerel was quick. His knife clipped the man across the forehead, missing the mask and digging into his diving hood, drawing a deep cut.