Sapphire and Conor can't forget their adventures in Ingo, the mysterious, fascinating world beneath the sea. They long to meet their Mer friends Faro and Elvira again.
But they've moved from their cottage on the cliffs, and from the cove which was their gateway into Ingo. Their mother wants to start a new life in the seaside town of St Pirans, away from the haunting memories of their father who disappeared at sea the year before.
A threat is growing deep beneath the surface of the sea, where the wisest of the Mer, Saldowr, guards the Tide Knot. Ingo is restless, danger is close, and soon both Sapphire and Conor will hear the call of the Deep. Their courage will be tested to the limit as the worlds of Mer and human come face to face.
I wake with a shock out of a deep, dreamless sleep. I'm completely disorientated, and have no idea how long I've slept. It must be morning. But my alarm clock reads 21.32, and someone is banging on the door downstairs. And shouting. It's Conor. His voice is loud and urgent. There's something wrong.
I jump up, fling open my door and rush downstairs. Roger is already at the front door, and there's Conor on the doorstep, with Mal, both of them streaming wet with rain.
' Conor! What's happened?'
' Dolphin stranded on Polquidden,' gasps Conor. He must have run all the way up. 'Mal's dad was night fishing - found it lying on the sand just now. Must've got stranded after dark. He's down there now.'
' Is it alive?'
' Just about. In a bad way though. We've called the emergency number and there should be a rescue team here soon. Is Mum still at work?'
'Yes,' says Roger. He's already pulling on his boots and waterproofs. 'I'll come down with you, Conor. I've done basic training on live strandings.'
Of course, you would have, I think. Is there any field in which Roger is not competent? I slide my bare feet into my own boots, and find my waterproof. I don't care if I'm grounded, I'm going, and no-one's going to stop me. Roger glances at me, but says nothing except, 'Don't bring Sadie. She'll stress the dolphin even more.'
We slam the door, remembering too late that none of us has a key. Conor has left his at Mal's. But there's no time to think, because we're already running down the street, turning the corner, and down the slippery rain-wet steps to the beach. The tide is out. It must be on its way in by now, but it's still far away. The dolphin would have got stranded on the falling tide. What happened to make it come so close inshore? Maybe it was sick, or injured, or it had been hurt in an encounter with a trawler, or something else had disorientated it -
We splash over the wide, empty beach, through the shallow pools that the sea has left, over hard ridged sand, towards a faint, bobbing light over by the rocks way down on the left hand side of the beach. The light is shrouded by rain.
' Where's Mal gone?'
' To fetch more help.'
We run as fast as we can towards the light. It seems near, then far, and sometimes there seems to be nothing on earth but rain and darkness and our own labouring breath. But we're getting close. Now we can see shapes in the darkness ahead. Roger raises his torch. There's a man - Mal's dad - and a curved bulk on the sand. It glistens with rain, like a wet black rock rising in a hump from the sand. But it's not a rock, it's the dolphin.
I have never understood what 'stranded' means, until the moment I see the dolphin lying there. The most graceful creature of Ingo lies helpless as a sack of sand. It cannot move. It cannot escape.
Roger's up ahead of me and Conor, shouting to Mal's dad. 'All right, Will? How are things?'
'Female, weighs about half a ton. It's not looking so good,' Will calls back. 'She's struggling.'
Struggling to survive, he means. She's not moving. Out of her element, stranded on the hard sand. She lies on her side.
' Don't reckon the tide'll come in fast enough for her.'
' Low water was about eight, that right?'
' That's right. Where are we now, half-past nine? Water should be back to her by half ten, eleven time.'
' Is she injured?'
' Bleeding from cuts on her flank. They're not too serious though. It's the pressure that's getting to her.'
'What pressure?' Conor asks.
'Once she's out of the water,' says Roger quickly, 'her own weight starts to crush her internal organs.'
Mal's dad swears softly. 'How many strandings is that round Cornwall this year? 'Bout eight hundred?'
'Twice what it used to be.'
'Terrible, it is. I blame those trawlers pair-fishing.'
All the time they're talking, they're moving around the dolphin cautiously, assessing her condition.
'Problem is,' says Will, 'could be a while before the emergency team gets here tonight. There's a live bottleneck stranded over at Gwithian, they're still busy up there, can't leave it. Bottlenecks are rare enough, let alone a live stranding.'
So this dolphin has only got us to help her. But the tide's rising, Maybe things are not so bad.
'Won't the sea float her off safely, as soon as the tide comes in?' I ask.
'It's not as easy as that. Soon as she's out of the water, see, her own weight starts to damage her, like Roger here said. We don't know what that damage may be. We need pontoons to support her, and a vet.'
More lights are coming down the beach.
' I hope Mal's not roused too many,' says Will, 'a crowd's the last thing she needs. Die of stress, a dolphin will.'
But it's only Mal, and a couple of older boys I recognise from the surf shop. And another figure, not as tall, face hidden by a cagoule hood.
She pushes back her hood. Her short, bright hair shines in the light of the lantern she's carrying. Her smile is so warm you'd think I was her oldest friend.
'Why are you here?' I ask. 'Sorry, I don't mean you shouldn't be here -'
'Patrick told me about the dolphin. That's Patrick over there, he's my stepbrother.'
They've brought more torches as well as the lantern, buckets and a bundle of what looks like cloth. Tarpaulin, Patrick says.
'Flat sea tonight, thank God,' says Will, 'Heavy surf come in on her now, she'd have no chance.'
No chance. No chance. But she mustn't give up. I kneel on the wet sand, by the dolphin's head. Rainbow crouches down beside me.
'Don't touch her,' says Roger sharply.
'We're not touching her.'
I want to shield her from the light of the torches and lantern. It's too much for her. She'll be even more afraid. She has never known a world without the strong salt sea all around her, buoying her up and taking her weight.
'Hold on,' I whisper to her. 'We're trying to help you. Please hold on.'
She says nothing, but her eye looks into mine. She is very tired, very far away. She has retreated deep inside herself, trying to survive. She doesn't want to give up her life, here on this cold hard earth.
'What can we do?' Rainbow whispers. 'She looks as if she's dying.'
'Don't say that. She'll hear you.'
'I'll get some water to pour over her skin. You're supposed to keep dolphin's skin wet, aren't you?'
It's still raining hard, but maybe sea water would be better for the dolphin than rainwater. It might comfort her.
'That's a good idea.'
Rainbow stands up, takes one of the buckets and heads off to the sea. She's right, it's good to do something practical to help, but I can't leave the dolphin. She feels so alone. She doesn't understand the air and the smell of land and the way we tramp round her in our big boots. Everything hurts.
Behind me there are low, angry voices. Mal's dad is arguing with the boys.
' You can't lift a live dolphin in a tarpaulin. That's for a dead stranding. You'll do more harm than good.'
'But she'll die if we do nothing,' insists Mal. 'Isn't it worth trying?'
' Manhandling a dolphin like that? You'll kill her. She's suffering from shock as it is.'
'I'm only trying to help.'
'Well, you're not helping, boy.'
'Call the rescue service again,' suggests Conor. 'Ask them what's best to do if they can't get here themselves.'
The dolphin is so big and so helpless. Another squall of rain hits us, and the roar of the tide is suddenly loud. But the white edge of breaking waves is still too far away to save her. No new lights bob down the beach. No rescue is in sight. Rainbow comes back with her bucket of sea water, and pours it carefully over the dolphin's back, avoiding her blowhole. She runs down to the sea again with the empty bucket. Does the dolphin like the salt water? Yes, I think it comforts her, but it torments her too. It has the smell and touch of home. Her home is within sight, but it might as well be a hundred miles away. The dolphin is helpless to move. I feel so frustrated I want to scream. The tide's rising, but not fast enough to save her.
Before long the water here will be so deep that I won't be able to stand. In less than an hour, maybe. The dolphin will float free. But by that time she might be dead. Why has the tide got to come in so slowly? Why has Ingo always got to follow its laws, when the law of tides might mean death for one of its creatures?
Maybe it doesn't have to. The dolphin is so afraid. She is so alone. She is calling inside herself, for the other dolphins of her pod. But they are somewhere out in the dark water, and they can't hear her. They'll be desperate too, trying to call her and find out where she is, but the air blocks their voices. She's so afraid of dying alone, out of the water, among strangers.
'You're not alone,' I whisper to her, 'I won't leave you, whatever happens.'
I lean closer. She wants me to touch her. She can't bear the touch of the sand, and yet her weight is making her sink deeper into its gritty harshness. Roger said her own weight could crush her internal organs. That means her heart, her liver, her lungs, all those vital parts of her. The thought of the dolphin's heart being slowly crushed makes me shudder.
'I'm sorry. I'm so, so sorry.'
Rainbow is back again. She sluices sea water over the dolphin's back, then kneels down beside me. The dolphin's tension and fear rise in her like a tide. She doesn't know Rainbow. Rainbow is part of earth, and threatening.
' Rainbow,' I begin awkwardly, not sure if she'll understand or be deeply offended, 'The dolphin, she's getting stressed with both of us here. She doesn't understand that you're trying to help.'
'I don't want to be with her,' Rainbow answers, getting up. Her voice is full of pain. 'It's horrible to see her suffering like this, and we can't do anything to help. I wish - I wish it was all over.'
'Don't say that! Fetch more sea water.'
Roger and Will are also down at the sea's edge, filling buckets. Rainbow wipes her hands on her jeans, and picks up her own bucket again. Then, like an echo of my own thoughts, she says,
'Tell her I'm sorry.'
Mal and the other boys are digging a channel in the sand, so that the rising tide will reach the dolphin as soon as possible. Should I help them? I weigh it up quickly, and then make my decision. The dolphin needs the trench to be dug, but her shock and fear are the greatest threat to her life. I am sure - almost sure - that I can support her -
'What are you doing, Saph?' asks Conor quietly, in my ear.
'She's so afraid, Con. She'll die of fear before the tide reaches her.'
'Roger said you shouldn't touch her.'
But my Mer blood is rising, growing stronger in answer to the call of the dolphin's desperate need. Ingo is powerful in me tonight. I know it. The touch from my hands is a Mer touch now, salt and reassuring. I am sure I feel the dolphin's anguish ease a little under my hands. But that won't be enough to save her. If only the sea would come quickly. If only Ingo would come to her daughter's rescue now. I stare down through the darkness at the pale line of foam where the tide is coming in. With all my heart I wish for Ingo to come. With all my heart I wish for Ingo to come.
I put my arms around the dolphin. I can feel her heart beating inside her, with slow, deep strokes. Her gaze in the lantern light is full of suffering. She must not die. I can't stop myself, I'm crying now, swallowing tears and tasting the salt.
'Hold on. Hold on, hwoer kerenza. They are all waiting for you out there. As soon as the water's deep enough, they'll come in to help you. You mustn't give up hope now.'