Zoe had been caught in the rain; as she dried herself by the fire, Mariana told them what had happened – and about her confrontation with Edward Fosca. When she finished, Zoe spoke in a low voice.

‘That was a mistake. Confronting him like that … Now he knows you know.’

Mariana glanced at Zoe. ‘I thought you said he was innocent?’

Zoe met her gaze and shook her head. ‘I changed my mind.’

Clarissa looked from one to the other. ‘You’re quite sure, both of you, then, that he is guilty? One doesn’t want to believe it.’

‘I know,’ said Mariana. ‘But I believe it.’

‘So do I,’ said Zoe.

Clarissa didn’t reply. She reached for the decanter and refilled her glass. Mariana noticed her hand was trembling.

‘What do we do now?’ said Zoe. ‘You’re not going to leave, are you?’

‘Of course not.’ Mariana shook her head. ‘Let him arrest me, I don’t care. I’m not going back to London.’

Clarissa looked astonished. ‘What? Why on earth not?’

‘I can’t run away. Not any more. I’ve been running since Sebastian died. I need to stay – I need to face this, whatever it is. I’m not afraid.’ The phrase sounded unfamiliar on her tongue. Mariana tried it again. ‘I’m not afraid.’

Clarissa tutted. ‘That’s the whisky talking.’

‘Perhaps.’ Mariana smiled. ‘Dutch courage is better than none.’ She turned to Zoe. ‘We keep going. That’s what we do. We keep going – and we catch him.’

‘How? We need some proof.’

‘Yes.’

Zoe hesitated. ‘What about the murder weapon?’

Something about the way she said this made Mariana look at her. ‘You mean the knife?’

Zoe nodded. ‘They’ve not found it yet, have they? I think – I know where it is.’

Mariana stared at her. ‘How do you know that?’

Zoe avoided her eye for a second. She kept looking away at the fire – a furtive, guilty gesture that Mariana recognised from childhood.

‘Zoe?’

‘It’s a long story, Mariana.’

‘Now’s a good time for it. Don’t you think?’ She lowered her voice. ‘You know, when I saw the Maidens, they told me something, Zoe … They told me that you were part of the group.’

Zoe’s eyes widened. She shook her head. ‘That’s not true.’

‘Zoe, don’t lie—’

‘I’m not! I only went once.’

‘Well, why didn’t you tell me?’ said Mariana.

‘I don’t know.’ Zoe shook her head. ‘I was afraid. I felt so ashamed … I wanted to tell you for so long, but I …’

She fell silent. Mariana reached out and touched her hand. ‘Tell me now. Tell us both.’

Zoe’s lip trembled a little, and she nodded. She began to speak, and Mariana steeled herself— And the very first thing Zoe said made Mariana’s blood run cold.

‘I suppose,’ Zoe said, ‘it begins with Demeter – and Persephone.’ She glanced at Mariana. ‘You know them, right?’

It took Mariana a second to find her voice.

‘Yes.’ She nodded. ‘I know them.’

2

Zoe drained her drink. She placed it on the mantelpiece. The fire was smoking slightly, and grey-white smoke swirled around her.

Mariana watched Zoe, with the red-and-gold flames dancing beneath her, and Mariana had a funny campfire-like feeling, as if she were about to be told a ghost story … Which in a way, she was.

Zoe began telling the story, tentatively at first, bit by bit, that Professor Fosca was so fond of – the secret rites at Eleusis to honour Persephone: rites that took you on a journey from life to death and back again.

The professor knew the secret, he said – and he shared it with a few special students.

‘He made me swear an oath of secrecy. I couldn’t talk about what happened with anyone. I know it was weird, but – I was flattered that he thought I was special enough – clever enough. And I was curious too. And then … it was my turn to be initiated into the Maidens … He told me to meet him at the folly, at midnight, for the ceremony.’

‘The folly?’

‘You know – it’s by the river, near Paradise.’

Mariana nodded. ‘Go on.’

‘Just before twelve, Carla and Diya met me at the boathouse, and escorted me – on the river, in a punt.’

‘A punt, why?’

‘It’s the easiest way to get there from here – the path is overgrown with brambles.’ She paused for a moment. ‘The others were there when I arrived. Veronica and Serena were standing by the entrance to the folly. They were wearing masks – meant to be Persephone and Demeter.’

‘Good God,’ said Clarissa, letting out an involuntary groan of disbelief. She quickly gestured at Zoe to continue.

‘Lillian led me into the folly – the professor was waiting there. He put a blindfold on me, and then – I drank the kykeon – which he said was just barley water. But he was lying. Tara told me later it was spiked with GHB – he used to buy it from Conrad.’

Mariana was feeling unbearably tense – she didn’t want to hear any more. But she knew she had no choice. ‘Go on.’

‘And then,’ Zoe said, ‘he whispered in my ear … that I would die tonight – and be reborn at dawn. And he took out a knife, and he touched my throat with it.’

‘He did that?’ said Mariana.

‘He didn’t cut me or anything – he said it was just a ritual sacrifice. Then he took off my blindfold … And that’s when I saw where he put the knife … He slid it into a gap in the wall – between two stone slabs.’

Zoe shut her eyes for a second. ‘After that, it’s hard to remember. My legs were like jelly, like I was melting … And we left the folly. We were in the trees … in the woodland. Some of the girls were dancing naked … the others were in the river, swimming – but I – I didn’t want to take my clothes off …’ She shook her head. ‘I don’t remember exactly. But I lost them, somehow – and I was alone, and high – and scared – and … he was there.’

‘Edward Fosca?’

‘That’s right.’ Zoe seemed unwilling to say his name. ‘I tried to speak but couldn’t. He kept – kissing me … touching me – saying he loved me. His eyes were wild … I remember his eyes – they were crazy. I tried to get away … But I couldn’t. And then – Tara appeared, and they started kissing – and somehow, I managed to get away – I ran through the trees – I kept running …’ She lowered her head, and fell silent for a moment. ‘I kept running … I got away.’

Mariana prompted her. ‘What happened then, Zoe?’

Zoe shrugged. ‘Nothing. I never spoke to the girls about it again – apart from Tara.’

‘And Professor Fosca?’

‘He acted as if it never happened. So I – tried to pretend it hadn’t.’ She shrugged. ‘But then Tara found me that night in my room … She told me he had threatened to kill her. I’d never seen Tara so scared – she was terrified.’

Clarissa spoke in a low voice. ‘Dear girl, you should have alerted the college. You should have told someone. You should have come to me.’

‘Would you have believed me, Clarissa? It’s such a crazy story – it’s my word against his.’

Mariana nodded, feeling close to tears. She wanted to reach out and pull Zoe into a hug and hold her.

But first, there was something she had to know.

‘Zoe – why now? Why are you telling us this now?’

Zoe didn’t speak for a moment. She went over to the armchair where her jacket was hanging, drying by the fire. She reached into the pocket.

She pulled out a slightly damp, rain-speckled postcard.

Zoe dropped it in Mariana’s lap.

‘Because I got one too.’

3

Mariana stared at the postcard in her lap.

The image was from a murky rococo painting – Iphigenia naked on a bed, with Agamemnon creeping up behind her, brandishing a knife. On the back, there was an inscription in Ancient Greek. Mariana didn’t bother to get Clarissa to translate. There was no point.

She needed to be strong for Zoe. She needed to think clearly and think fast. She kept all emotion out of her voice.

‘When did you receive this, Zoe?’

‘This afternoon. It was under my door.’

‘I see.’ Mariana nodded to herself. ‘This changes things.’

‘No, it doesn’t.’

‘Yes, it does. We need to get you out of here. Now. We need to go to London.’

‘Thank goodness for that,’ said Clarissa.

‘No.’ Zoe shook her head. She had a fiercely stubborn look on her face. ‘I’m not a child. I’m not going anywhere. I’m staying here, like you said – we’re going to fight. We’re going to catch him.’

As she said this, Mariana thought how vulnerable Zoe looked, how tired and wretched. Recent events had visibly affected and altered her – she looked mentally as well as physically beaten up. So fragile, yet so determined to keep going. That’s what bravery looks like, thought Mariana. This is courage.

Clarissa also seemed to sense this. She spoke in a quiet voice.

‘Zoe, dear child,’ she said, ‘your bravery is commendable. But Mariana is right. We must go to the police, tell them everything you’ve just said … And then, you must leave Cambridge – both of you. Tonight.’

Zoe pulled a face and shook her head. ‘No point in telling the police, Clarissa. They’ll think Mariana put me up to it. That’s a waste of time. We don’t have time. We need evidence.’

‘Zoe—’