It was my grandpa who lured Old Methuselah out from the tannic depths of the lake. We were fishing for marron in the shallow waters of a small bay beside the dam wall, the jarrah forest at our back. The water dropped beneath the dam wall, and grandpa tossed the meat tied to a string into the deeper water, slowly dragging it in. I can still see the wet, wiry hairs on the backs of his hands as he murmured ‘Oh boy' at the sight of the hulking marron, following the meat. Old Methuselah lurked, scarred and ancient, claws raised in defence, rolling across the lake floor. But we were never able to catch it, then or in the years that followed. It was too clever. My grandpa called it a ‘worthy adversary'.

We talked about Old Methuselah in the weeks leading up to my grandpa's death, before his body closed down and he was unable to talk. My grandpa lurked there, somewhere in his body, wise and old and patient, watchful behind the fear and confusion in his eyes.

I had always avoided the drain but after my grandpa died I went there more and more. It was a vertical shaft built into the dam wall that descended into black nothingness. If you dropped a rock you couldn't hear it splash. Old Methuselah lived down there, and perhaps other things too. A single pole seven metres long was laid across the drain, welded into place. I imagined tightrope-walking the pole, from one side of the drain to the other, but the thought made me feel sick.

I never understood why my step-father didn't like me. My mother married him after my grandpa died. My step-father was an explosives expert who worked out on the mines. I looked forward to the weeks that he was away, and dreaded his return. He could never hide the sneer on his face when he looked at me. I was ‘part of the package' he told me, ramming through the gears as we drove to the lake. He hoped I was grateful for him taking me fishing, even though ‘it was part the deal.'

My step-father tinkered with his dirt-bike while I caught smaller marron. When I had caught enough, the inky black bodies slamming in the bucket, I tipped them back in and watched them scurry away. I went further round the bay to the base of the dam wall and began to lure Old Methuselah out of the depths. Sure enough, there he was, inching behind the meat, too clever to grasp it. Old Methuselah, who lives outside of time, my grandpa always said, and I was glad to see that he hadn't grown, or aged.

We watched each other across the distance of air and water. I didn't notice my step-father behind me, until he shouted ‘fire in the hole' and grabbed my shoulders, pulling me back. The stick of TNT exploded on the water and sent a geyser of spray into the air. My step-father laughed while the water cleared. Old Methuselah tilted on his side, rolled onto his back, then fell away into the depths.

I sprang to my feet and ran away, up the scree slope of the dam wall. When I reached the top, I climbed onto the lip of the drain and put my left foot on the pole. Then I was walking, looking down into the black nothingness, until I reached the other side.