He straightened his back, and watched the distant others for a moment, returning in a long, stretched-out line of orange figures. By the set of their shoulders, they’d been less than successful and less than satisfied with the state of affairs. They looked beaten, in fact: all except Stanislav. He seemed to still be walking with purpose.

‘This’d be easier with a net,’ Mary said, not taking her eyes off the river between her feet.

She was right. They didn’t have one, though. Could he could make one?

He was used to wires and circuits, motors and controls. A net wouldn’t need more than a forked piece of wood, and a bit of thin cloth. Still cross with himself over his earlier failure with the torch, he thought about construction without suitable tools as he went back out on to the estuary to look for more nests, and more eggs.

He had supposed there was going to be a main channel to the river, but he blundered into it to above his knees before he realised. The wide stretch of water was rippling as the tide ran up against the downstream flow.

The fish, which on the edges of the estuary wafted their tails lazily, had to swim hard against the current. Their sail-like fins and gleaming backs flashed as they broke the surface, scattering light and water.

There was a sudden roar, and an eruption of white foam. Dalip fell back into the reeds, and a black shape with scales the size of shields leapt up and lunged forward. The wave hit him hard, and the backwash dragged at his boilersuit. The creature shook its head, spray flying from its closing mouth, pin sharp teeth ivory white against its skin.

It ducked back down. The water slapped closed over it, and the waves subsided.

He scrambled further back, using his feet to push him away. It took him a moment to realise that he was whole, and another to realise that the first rush of water had been more fish than river. They flapped and wriggled, eventually squirming into the nearest channel and darting away.

The sea serpent was so much bigger than he’d expected. He sat up in time to see the tip of its tail churn the water with a v-shaped wake. A moment later, upstream and swimming hard, it burst out again, mouth wide and full of prey.

Mary was running towards him. What she thought she could do escaped him, and he quickly waved her back, while setting off at a jog towards her across the braided streams and sandbanks. He was soaked, and must have looked more like a drowned rat than anything else, breathing hard, heart hammering in his chest.

He finally turned and tried to see how far the serpent had gone upstream. From where he stood, both it and the deep channel were invisible.

‘Are you all right?’ Mary called.