‘Let’s go down. Be great to see it up close.’

I stared around. The sky was clearing over the swamp. The Waimoana seemed to have reached right into the flax and reeds. The door of our hayshed stood open, but nobody was in sight.

Yeah, we could climb down and stand on the rocks that the water was sweeping across. It was fast, but only ankle-deep. If we held onto the sides of the bank, we’d be fine. OK, Mum had told us not to, but we wouldn’t be in the dangerous part.

My friend was already out of his oilskin and kicking off his gumboots. I took another look around, then started taking off my boots and coat as well. We piled them on top of the bank.

Tipene began clambering down. There were handholds — a stone, a hollow in the bank, a tree root — that we used when we went there to swim. I followed. The clay was muddy; I’d have to be careful not to get too much on my clothes, or Mum would want to know where we’d been.

My feet touched something. ‘Don’t tread on my head!’ Tipene yelled. He was a poet, too? He stared at the water sweeping across the stony surface below him, looking for a place to put his own feet.

‘Why not?’ I called back. ‘Your head’s harder than a rock!’ We both started sniggering.

Tipene reached a leg down. Then he was standing, the muddy water sluicing around his shins. He staggered for a moment, grabbed at the bank, and said, ‘It’s OK. Come down.’

I let go of the root I was holding, reached down for a hollow in the bank, and followed. The clay was so sodden, it came away in my hand. I half-lurched, half-dropped onto the rock beside my friend, clutching at him as I did so. We both reeled sideways, then stood with the water skimming past.

‘You’ve ruined that handhold.’ Tipene stared at the gouge in the bank where clay had slumped away. ‘We’ll have to get back up a different way.’

I took no notice. I pointed at the small ledge, our hiding place. ‘What’s that?’

Tipene turned to look. I heard his breath stop.

The square piece of wood was just a few feet away. We were close enough to see the shapes on its side. Whorls, curves, a face with a tongue pushed out. Silver and blue glowed. A pair of paua-shell eyes, set into the wood.

Tipene’s voice was hushed, but I could hear him above the rush of water. ‘The river left it there. It’s — it must have come from the swamp.’