Ffion was next, swimming straight into Gruff’s air bubble and erupting in surprised laughter. She was up on her feet and squeezed in beside Tim before Gruff had to explain what to do, and she reached with her whole upper body through the skin of water and dragged Hardik in to join them.

‘Yellow!’ Tim shouted in Gruff’s ear, and all the hands on his shoulders steered him to the left, Hardik and Ffion now shouting too. ‘Yellow! Mair – your nain!’

Gruff saw it. Nain’s yellow sou’wester, bright and defiant in the belly of the wave. He ploughed towards the colour as fast as he could, and arms reached past him and grabbed fistfuls of coat, pulling Nain in to safety. Gruff felt a sob of relief rise in him but he swallowed it down. So many still missing. So many still to find.

‘To the right!’ Nain cried, as soon as she had caught what breath she could. ‘I saw Deepa there!’

But even as she spoke, Gruff felt the movement of the wave change. It had been driving towards him and past him as he cut into it but now that force slowed … and paused. For a silent second, all was still.

‘Gruff!’ Ffion gasped. ‘You’ve got to get behind us!’

The wave smashed into their backs. The four adults stumbled into Gruff and he fell forwards, dropping the sword. It returned instantly to water.

Gruff blundered backwards through the struggling bodies, feeling for the sword hilt. Its cool, writhing surface formed in his palm and he gripped it and slung upwards into the backwash of the wave that was trying to sweep them all out to sea.

The wave was too solid and the sword cuts not deep enough to create a bubble, but he managed to curb the power of it near the ground and find his feet, the four adults clinging onto him and one another. He cut again and again into the water, keeping them all in one place as the wave rushed around them and over them and out to sea. Somewhere in that wave were the people he had not found: Deepa, Jack, Dafydd, Rosie, John. And though Gruff tried not to let the word be thought, it was in every swipe of the sword in front of him: drowning, drowning, drowning.

The wave was spent. Gruff stood near the head of the beach, water up to his chest. Tim, Ffion and Hardik helped Nain scramble up the sea wall. Gruff ignored their calls and forced his way down the beach until the water was up to his chin. He held the sword ahead of him, though he could not cut a path through this aimless pool. The sea was gathering itself for another attack. There was no sign of the missing.

Gone. My fault.

Dylan erupted from the water in front of Gruff, his sharp teeth bared. His polluted wound stank, the sickly stench of long-drawn-out agony.

Gruff tried to hold his ground in the heaving water. ‘Peidiwch!’ he said. Don’t. Salt water slapped into his mouth and he coughed, his words coming out in gasps. ‘You’ve got my friends. You’re drowning them. Please.’

Dylan showed no sign he had heard. Gruff followed the morgen’s storm-filled gaze and saw what had brought him out of the water, understood what was causing the waves to buck and roil in fear and anger.

It was the sword. Gruff was holding it at chest height in front of him, half the blade protruding from the swell. It rippled with glints of light. The last time Dylan had seen this sword, it had been just a hilt and beautiful sounds. Swimming towards it had cost him everything. His sunken eyes were filled now with such hatred, such dread…

Gruff released his grip on the hilt, but even as he did so, Dylan’s webbed hand reached out. In the moment before the sword left Gruff’s grasp and melted into water droplets, the morgen’s fingers closed around the fluid-soft, steel-sharp blade.

Dylan gasped.

‘Sorry! Sorry!’ Gruff braced himself and flung his arms up to protect his head, waiting for the sea to thunder down on him in retribution for Dylan’s new wound.

The sea did not thunder. In fact, the sea didn’t seem to do anything at all.

Gruff raised his head slightly and peered out between his arms.

Dylan was nowhere to be seen. The choppy white horses lessened and lessened until they vanished into tiny ripples. Very slowly – Gruff felt the change, his whole body rocking gently forwards in the subtle shift of power – the sea began to retreat. Out in the open water, the waves were gone.

‘What?’ Gruff whispered.

The sudden calm brought quiet, and Gruff realised that he could hear calls for help. He turned towards the noise and saw the five lost flood-fighters swimming with exhausted limbs towards the shore.

‘YES!’ he yelled. The water was only up to his knees now and he started towards the newly-uncovered lifebuoy stand. Hardik and Ffion got there before him and came wading and then swimming with the orange plastic ring to meet the group.

Gruff saw that Rosie and Deepa were supporting John, whose splashing suggested he was not a strong swimmer. Dafydd had his husband Jack in a lifeguard’s hold, his hand under his chin, and Gruff’s heart tightened horribly – but when Hardik and Ffion arrived with the ring, Jack grabbed it himself and Gruff heard him half-laugh and say, ‘Leg cramp. I’m okay.’

Rosie and Deepa brought John to the ring, then they and Dafydd joined Hardik and Ffion swimming to shore. Tim, Nain and the bed-and-breakfast guests pulled the life ring’s rope, hand over hand, dragging their catch to safety.

Gruff headed towards them all, relief making his legs wobbly. There was no water round him now. The tideline was almost back to where it ought to be, leaving seaweed and crabs and rubbish strewn on the sand.

And something else. Something like a man, but not a man. Something beached, something helpless. A sprawling figure with webbed feet and hands and dull grey scales, abandoned by the water.

Gruff stopped. ‘Dylan?’ he called.

No movement.

‘Dylan?’ Gruff ran down the beach towards the motionless figure. He thumped to his knees at the morgen’s side. ‘Are you okay?’ he asked.

Dylan opened his eyes and looked straight at Gruff. He managed a tiny smile of recognition, and Gruff could see that this Dylan was the one he had talked to at the Sleepers, not the one who had caused the storm. This Dylan knew who Gruff was, and would listen to him when he spoke.

Dylan was making a small, rhythmic choking noise in the back of his throat. Gruff winced. ‘You can’t breathe.’ He scooped his hands under Dylan’s ragged body and lifted him without thinking. Internal waves lapped up Gruff’s arms. The morgen was lighter than he had expected, no heavier than Prem.

As he stumbled to his feet, Dylan in his arms, Gruff heard a steady dribbling sound that made his heart lurch. ‘You’re bleeding,’ he said, and he looked for the deep cuts he was sure Dylan had suffered from clutching the sword blade. But there were no wounds.

There were no wounds, because there was no hand.

Gruff concentrated hard on not letting his knees collapse beneath him.

Dylan’s arm stopped at the elbow. Instead of a bloody stump, clear water bubbled from it, as though he was an ice sculpture melting in the sun.

Dylan began to shudder and retch. Gruff came to his senses and half-ran down the beach into shallow water. He pushed on until the gentle waves were at his shaking knees, and then knelt and placed Dylan down, submerging him fully.

As Gruff withdrew his arms, Dylan’s remaining hand found his and took it in a cold, scaly-soft grasp. Gruff sat cross-legged, the water up to his chin, and waited for Dylan to find the breath and energy to speak. He needed to know what had happened. He needed to know if he could help. Gentle wavelets washed from Dylan to Gruff, mirroring the calm sea around them.

The wind had died to a whisper. Overhead, the clouds were thinning and burning up in the heat of the morning sun. The storm was the memory of a nightmare.

Gruff thought of the lifeboat, and tried not to think of the lifeboat. He thought of Mat, and wished she would pop up next to him, grinning and safe.

Dylan’s grip grew tighter as his strength returned. At last his face appeared above the surface and he looked at Gruff with smiling eyes imbued with a gentle swell.

‘I didn’t know the sword had this power,’ Dylan said.

‘Me neither.’

‘And Gofannon can’t have known,’ Dylan added, ‘or she would have instructed you to do deliberately what was done by accident.’

‘But what have I done?’ Gruff’s stomach clenched and unclenched, bile rising in his throat. Was Dylan disintegrating because of him?

Dylan smiled. ‘You held the sword, and I touched the blade. It’s forged with magic and I’m not mortal. Instead of cutting me, it’s severed me from this decaying body.’

‘But does that mean…’ Gruff licked his salt-cracked lips. ‘I – I’ve killed you? I didn’t mean to! I tried to drop the sword, I…’

Dylan squeezed Gruff’s hand. ‘You haven’t killed me. You have given me my life.’

Gruff saw that Dylan’s arm was now entirely gone. His chest, and the terrible ancient wound there, bubbled gradually away in a spring of clear water that spread down his legs and crept up towards his neck.

‘You have saved me,’ Dylan said, and his voice seemed to strengthen even as he melted away. ‘You’ve ended a storm that began long ago. And you fought me bravely today, wielding that sword – you and the morgen I haven’t met; she was out here too, wasn’t she? I sensed the calm she spread through my anger. You saved lives when I would have taken them. You stopped me accomplishing what I never intended to do.’

Gruff thought of the lifeboat carrying Dad and Zosia and all the others, of the boat they had gone to rescue, of Mat swimming out into the tempest alone. I hope so, he thought.

‘I am one with the sea,’ Dylan whispered. He closed his eyes as his body merged with the rippling water. ‘I am home.’

Dylan’s webbed, scaly grip rushed out from between Gruff’s fingers and then there was just his face, upturned to the sky, his lips quirked into a smile of playfulness and peace.

Then Dylan was gone, and Gruff sat alone in the shallows.