Husband and wife began by filling the hot tub with cold water and pieces of ice fetched in buckets from the lake. It didn’t take long because it was only a few yards to the water’s edge. The weather was cold and Baldvin told María that she should wear as little as possible outside so as to accustom herself to the cold before immersing herself in the tub. Finally he bashed ice off the rocks on the shore and filled the tub with it. By now María had taken two mild sleeping tablets that he said would help to dull the cold.

María recited a psalm and a short prayer before lowering herself slowly into the tub. The cold was like knives driving into her but she put a good face on it. She entered the water slowly, first up to the knees, then the thighs, hips and stomach. Then she sat down and the water reached above her breasts, shoulders and neck until only her head remained above it.

‘Are you okay?’ Baldvin asked.

‘It’s… so… cold,’ María gasped.

She couldn’t control her shivering. Baldvin said it would stop after a while when her body had given up fighting the cold. It wouldn’t be long before she lost consciousness. She would begin to feel drowsy and she shouldn’t resist it.

‘Normally, the rule is that you’re supposed to fight off drowsiness,’ Baldvin said, smiling. ‘But not in this case. You want to fall asleep. Just let it happen.’

María tried to smile. Before long her shivering ceased. Her body was completely blue with cold.

‘I must… know… Baldvin.’

‘I know.’

‘I… trust… trust you,’ she said.

Baldvin held a stethoscope to her heart. Its beating had slowed rapidly. María closed her eyes.

Baldvin listened to her heartbeat growing feebler and feebler.

Finally it stopped. Her heart had stopped beating.

Baldvin looked at his watch. Seconds passed. They had discussed waiting one to one and a half minutes. Baldvin reckoned that was safe. He held María’s head out of the water. The seconds ticked away. Half a minute. Forty-five seconds. Every second felt like an eternity. The second hand hardly seemed to move. Baldvin became uneasy. A minute. One minute, fifteen seconds.

He reached under María’s arms and with one good heave hauled her out of the tub. He wrapped a woollen blanket round her body, carried her into the cottage and laid her down on the floor by the largest radiator. She showed no sign of life. He began to administer mouth-to-mouth respiration and then to massage her heart. He knew he didn’t have much time. Perhaps he’d left her in the water too long. He blew air into her lungs, listened for a heartbeat, massaged her heart again.

He laid his ear against her chest.

Faintly, her heart began to beat. He massaged her body with the wool blanket and moved her closer to the radiator.

Her heart began to beat more rapidly. She drew a breath. He had managed to resuscitate her. Her skin was no longer bluish-white. It had regained a slight flush.

Baldvin heaved a sigh of relief and sat down on the floor, watching María for a long time. She looked as if she were sleeping peacefully.

She opened her eyes and stared up at the ceiling, a little bewildered. Then, turning her head towards him, she gazed at him for a long time. He smiled. María began to shiver violently.

‘Is… it over?’ she asked.

‘Yes.’

‘I… I… saw her,’ she said. ‘I saw her… coming towards me…’

‘María…’

‘You shouldn’t have woken me.’

‘It was more than two minutes before you came back to life.’

‘She was… so beautiful,’ María said. ‘So… beautiful. I… wanted to hold… to hold her. You shouldn’t have… woken me. You shouldn’t… have… done it.’

‘I had to.’

‘You… shouldn’t… have… woken me.’

Baldvin looked gravely at Erlendur. The doctor was on his feet, standing by the radiator where he claimed that María had lain when she had come back to life after dying in the hot tub.

‘I couldn’t let her die,’ he said. ‘It would have been easy. I wouldn’t have needed to revive her. I could have laid her in the bedroom and she’d have been found there the following day. No one would have noticed anything. An ordinary heart attack. But I couldn’t do it.’

‘Oh, aren’t you noble?’ Erlendur sneered.

‘She was sure that there was something there on the other side,’ Baldvin said. ‘She claimed she’d seen Leonóra. She was very weak at first after she woke up so I put her to bed. She fell asleep and slept for two hours while I emptied the tub, cleaned it out and tidied up.’

‘So she wanted to go back for good this time?’

‘It was her choice,’ Baldvin said.

‘Then what? What happened after she woke up?’

‘We talked. She had a clear memory of what had happened when she’d crossed over, as she called it. Most of it was like what people describe: a long tunnel, light, friends and relatives waiting. She felt she had found peace at last.’

‘Tryggvi said he’d seen nothing. Just blackness.’

‘I expect you need to be receptive to it. I don’t know,’ Baldvin said. ‘That was María’s experience. She was in a very good state of mind when I left to go back to town.’

‘You came in separate cars?’

‘María was going to stay here a bit longer to recover. I spent the night here with her, then went back to town at lunchtime the following day. She called me in the evening, as you know. By then she had recovered completely and seemed very cheerful on the phone. She was intending to be home before midnight. That was the last I heard from her. You couldn’t tell she was planning something stupid. It didn’t occur to me that she would take her own life. Didn’t even cross my mind.’

‘Do you think your little experiment was the trigger?’

‘I don’t know. In the period immediately after Leonóra died I had the feeling that María might do something like that.’

‘Don’t you feel the slightest responsibility for what happened?’

‘Of course… of course I do. I feel responsible but I didn’t kill her. I could never have done that. I’m a doctor. I don’t kill people.’

‘There are no witnesses to what occurred when you and María were here?’

‘No – we were alone.’

‘You’ll be struck off.’

‘Yes, probably.’

‘But that’ll hardly bother you now that you’ve inherited María’s money?’

‘Think what you like of me. I don’t care.’

‘And Karólína?’

‘What of her?’

‘Did you tell her that you’d changed your mind?’

‘No, I hadn’t talked to her… I hadn’t spoken to her yet when I was told that María was dead.’

Erlendur’s mobile phone started ringing. He retrieved it from his coat pocket.

‘Hello, it’s Thorbergur,’ a voice said at the other end.

‘Who?’

‘Thorbergur, the diver. I’ve made a few trips to the lakes east of Reykjavík. I’m there now.’

‘Oh, yes, Thorbergur – I’m sorry, I was being dim. Is there any news?’

‘I think I’ve found something that will interest you. I’ve ordered a small crane and notified the police, of course. But I daren’t do anything more without you here.’

‘What have you found?’

‘A car. An Austin Mini. In the middle of the lake. I didn’t find anything in Sandkluftavatn, so I thought I’d check out the lakes round about. Was it freezing when they went missing?’

‘Yes, it’s not unlikely.’

‘She must have driven out on the lake. I’ll show you when you get here. I’m up at Lake Uxavatn.’

‘Was there anyone in the car?’

‘There are two bodies. A man and woman from what I can tell. Unrecognisable, of course, but it looks like they’re your people.’

Thorbergur was silent for a moment.

‘It looks like they’re your people, Erlendur,’ he repeated.