They pushed the canoe through the rough waters of the outer seaward lagoon until the passage between the barrier islands had opened up. All the while the manisaur had shadowed them on the beach.

Maggie pulled alongside Peter and grinned. ‘That manisaur is not so scary… when it stays on that side of the water.’

Peter did not tell Maggie that he worried about more than the manisaur. He had seen the Jaws movies too many times. His mum had loved scaring him for some reason. They turned towards Black Spire island.

‘It’s hard to be sure of where Moby helped me, took me from. Which beach. But we can walk back to it. Find my boat.’

‘I don’t care. As long as it is away from that manisaur chasing us.’

A third of the way across, with no sign of the manisaur following, Maggie puffed up her baggy bathing shorts with air. They rested on their backs for a time. Then Peter squeezed his eyes shut to hide from the glare of the bright sun, and they resumed their rhythmic kicking and stroking.

Peter’s foot hit something, he opened his eyes, and pulled up. ‘We almost ran aground.’ His knees rested on a sandy floor.

Maggie flopped in the sandy shallows with a big grin. The water washed over the sandbar in a complex crossing of waves. Fish darted just under the surface. Black Spire island still lay far away.

Maggie pulled up to the edge of the outrigger and kicked while Peter walked it forward in the shallows. The wheel banged his back again.

’So much easier,’ Maggie said.

The sand bar formed an ‘almost island’ in the middle of the lagoon. He walked up to his knees, sometimes deeper, often shallower, but the sand bar never broke the surface. He marked the location in his memory. It would not pay to sail over this patch and hit bottom.

Was it high tide, or low? Where was the sun? High in the sky now. Did that mean the tide was high?

They reached the end of the sand bar where the water grew deeper once more and pushed on. The Black Spire seemed closer now. They were tiring but one last push would bring them safe to shore.

‘I wish we had been able to get more water,’ said Maggie.

Peter was bone tired but his thoughts still spun.

Support the author by searching for the original publication of this novel.

If the manisaur can swim, but chooses not to for some reason. Is there some vicious animal in the lagoon?

But that was the last thing Maggie needed to hear, and wished he had never thought of it himself.

‘It would have been another twelve hours until the water came back,’ Peter said. ‘Even if we had escaped the manisaur.’

‘Why would that be?’ Maggie said. She stopped kicking and rested a moment.

‘If we’re right,’ Peter said. He floated on his back, then flicked his hair free of water, then moved alongside Maggie. ‘The fresh water floats on top of the salt water…’

‘I’m sure of it,’ Maggie said. ’When it rains, the water drains away into the sandy ground until it hits the water table formed by the sea water. Then it floats and only mixes a little. My uncle has a bach at Waimairi Beach, and I remember he said something about the water table in the well. If they pumped too much too fast it got salty, but slow enough and the water remained sweet.’

‘And the sea rises and falls with the tide, twice a day. The Moon and the Sun act together to pull at the water, up and down.’

‘That can’t be right,’ Maggie said. ‘How can the Moon pull at water? Must be another reason for tides.’

‘Gravity. The Moon orbits the Earth every 29 days or so, phases and all that,’ Peter said. ‘So the time of high tide changes everyday.’ Peter began to push the canoe forward again.

‘How do you know it works like that here?’ Maggie said.

‘I don’t know. But some things are the same like you said.’

Maggie began to kick with Peter. The day had been hot and muggy but the wind remained from the east, so now it helped them on their way. Peter began to think how a sail might work. He would rather sail than this swimming-kicking nonsense.

‘Maybe what brought us here also brought coconuts,’ Peter said. ‘But a big moon like Earth’s must be pretty rare, and it wouldn’t appear the same.’

‘I’m sure I’ve seen the Moon. Let’s check tonight. And find constellations — Orion, the Southern Cross…’

‘Yeah,’ Peter said. ‘The stars would be all different on another planet.But we might be able to guess our latitude.’

‘You mean if we’re in the Northern hemisphere or…’

‘No. We’re in the South for sure. The Sun here goes right to left across the sky. Anti-clockwise.’

‘Yes — it’s clockwise in the North, probably why clocks go around that way.’

‘First time I saw the sun going backwards — freaky.’

‘Whereabouts?’

‘Japan.’

‘You must like Japan a lot.’ Maggie frowned.

‘The food, crazy huge cities. Anime…’

‘I’m going to ignore you.’ She kicked harder as if to make the point.

‘Anime is animation. Like Disney cartoons, but not kids stuff.’

Maggie shook her head. ‘You do that on purpose I think.’

‘What?’

‘Mention all the things that are different between our times.’

‘Hard not to. What would you talk about to your teenaged grandmother? Would she know about radio, movies, airplanes, and cars.’

‘I think she’d know about radio. And cars.’

‘Maybe. But not airplanes.’

‘Everything either of us knows is irrelevant here. Or it’s not real at all.’

Peter put his head down, rested his arms and kicked. She was right. All his knowledge was useless. And she must be tired of all his talking. How were you meant to make good conversation? Ask questions and agree. But how to find a question she could answer.

Peter and Maggie pushed the canoe and kicked on towards Black Spire island, oblivious to the silhouette fast approaching.

The darkness in the water moved towards them, like the shadow of a cloud, or a enormous shoal of fish.

But it wasn’t any of those.