Perhaps he had seen her and deliberately given her the slip? There was no point in going on.

She was about to turn back when a large statue caught her eye: a male angel, mounted on a cross, arms outstretched, with large, chipped wings. Mariana stared at the angel for a moment, mesmerised. The statue was tarnished and broken, but still beautiful – he looked a bit like Sebastian.

And then Mariana noticed something – just beyond the statue, through the foliage – a young woman walking on the path. Mariana recognised her at once.

It was Serena.

Serena didn’t see Mariana, and she approached a flat-roofed, rectangular stone crypt that once had been white marble but now was speckled grey and mossy green, with wildflowers growing around it.

She sat on it, took out her phone, and looked at it.

Mariana hid behind a nearby tree. She peered through the branches.

She watched as Serena looked up – at a man emerging from the foliage.

It was Morris.

Morris went up to Serena. Neither of them spoke. He took off his bowler hat and balanced it on a headstone. Then he grabbed the back of Serena’s head – and with a sudden, violent movement dragged her up, kissing her hard.

Mariana watched as Morris lay Serena down on the marble, still kissing her. He climbed on top of her. They started having sex – aggressive, animalistic sex. Mariana felt repulsed, yet also transfixed – unable to look away. And then – as abruptly as they had begun – they climaxed, and there was silence.

They lay still for a moment. Then Morris got up. He adjusted his clothing. He reached for his bowler and dusted it off.

Mariana thought she had better get out of there. She took a step backwards – and a twig snapped beneath her foot.

There was a loud crunch.

Through the branches, she saw Morris look around. He motioned to Serena to keep quiet. Then he moved behind a tree and Mariana lost sight of him.

Mariana turned and hurried back to the path. But which way was the entrance? She decided to go back the way she had come, along the wall. She turned around—

And Morris was standing right behind her.

He stared at her, breathing hard. There was silence for a few seconds.

Morris spoke in a low voice. ‘What the fuck are you doing?’

‘What? Excuse me.’ She tried to walk past him – but Morris blocked her path. He smiled.

‘Enjoy the show, did you?’

Mariana felt her cheeks burning, and looked away.

He laughed. ‘I see through you. You don’t fool me, not for a second. I’ve had my eye on you, right from the start.’

‘What’s that supposed to mean?’

‘It means don’t stick your nose in other people’s business – as my old grandpa used to say – or it’ll get sliced off. Get it?’

‘Are you threatening me?’

Mariana sounded braver than she felt. Morris just laughed. He gave her one last look, then turned and sauntered off.

Mariana stood there, shaking, scared, angry, and close to tears. She felt paralysed, rooted to the spot. Then she looked up and caught sight of the statue – the angel was staring at her, arms outstretched, offering an embrace.

She felt an overwhelming longing for Sebastian at that moment – for him to take her in his arms, hold her, and fight for her. But he was gone.

And Mariana would have to learn to fight for herself.

6

Mariana took the fast train to London.

It didn’t stop at any stations on the way, and seemed to be racing to its destination. It felt as if it were going too fast – jolting and bumping madly on the tracks, swinging and swaying out of control. The rails were squealing – a high-pitched wail in Mariana’s ears – like someone screaming. And the carriage door didn’t close properly. It kept opening and slamming shut, each bang startling and intruding on her thoughts.

There was a lot to think about. She felt deeply unsettled by her confrontation with Morris. She tried to make sense of it. So he was the man Serena was secretly seeing? No wonder they kept it secret – Morris would lose his job if his affair with a student was discovered.

Mariana hoped that’s all there was to it. But she doubted it, somehow.

Morris had something to do with Fosca, but what? And how was it related to Serena? Were they blackmailing Fosca together? If so, it was a dangerous game, antagonising a psychopath – one who had killed twice already.

Mariana had been wrong about Morris, she saw that now; she had fallen for his old-fashioned act – but he was no gentleman. She thought of the vicious look in his eyes when he threatened her. He wanted to scare her – and he’d succeeded.

Bang – the carriage door slammed, making her jump.

Stop it, she thought. You’re driving yourself crazy. She had to distract herself, think about something else.

She pulled out the copy of the British Journal of Psychiatry that was still in her bag. She flicked through it, and tried to read it – but couldn’t focus. Something else was bothering her: she couldn’t get over the sensation that she was being watched.

She looked over her shoulder, around the carriage – there were a few people in it, but no one she knew, or at least no one she recognised. No one appeared to be watching her.

She couldn’t shake it, though – the feeling of being observed. And as the train neared London, an unnerving thought occurred to her.

What if she was wrong about Fosca? What if the killer was some stranger – invisible to her, and sitting right here, in this carriage, watching her now, this very second? Mariana shivered at the thought.

Bang – went the door.

Bang.

Bang.

7

The train soon pulled into King’s Cross. As Mariana left the station, she still had that lingering feeling of being observed. The prickling, creeping sensation of eyes on the back of her neck.

Suddenly, convinced someone was right behind her, she spun around – half expecting to see Morris—

But he wasn’t there.

And yet the feeling persisted. She arrived at Ruth’s house feeling unsettled and paranoid. Perhaps I’m crazy, she thought. Perhaps that’s it.

Crazy or not, there was no one she would rather see than the elderly lady waiting for her at No. 5, Redfern Mews. It felt a relief just to press the doorbell.

Ruth had been Mariana’s training therapist when she was a student. And when Mariana qualified, Ruth began acting as her supervisor instead. A supervisor plays an important role in a therapist’s life – Mariana would report back to her about her patients, her groups, and Ruth would help Mariana unpack her feelings, distinguishing between her patients’ emotions and her own, which wasn’t always easy. Without supervision, a therapist might easily get overwhelmed and emotionally swamped by all the distress she had to contain. And she might lose that impartiality that was so important to working effectively.

Following Sebastian’s death, Mariana began seeing Ruth more frequently, needing her support more than ever. It was therapy in everything but name – and Ruth suggested she should fully commit: return to therapy, and have Ruth treat her. But Mariana refused. She couldn’t explain why exactly, other than she didn’t need therapy; she just needed Sebastian. And all the talking in the world couldn’t replace him.

‘Mariana, my dear,’ said Ruth, opening the door. She gave her a welcoming smile. ‘Won’t you come in?’

‘Hello, Ruth.’

It felt so good to go inside, and enter the living room that always smelled of lavender, and hear the silver clock ticking reassuringly on the mantelpiece.

She sat in her usual seat, on the edge of the faded blue couch. Ruth sat opposite her, in the armchair.

‘You sounded quite distressed on the phone,’ Ruth said. ‘Why don’t you tell me about it, Mariana?’

‘It’s hard to know where to start. I suppose it started when Zoe called me that night, from Cambridge.’

Mariana then began telling her story, as clearly and comprehensively as she could. Ruth listened, nodding occasionally but saying very little. When she finished, Ruth remained silent for a moment. She sighed, almost imperceptibly – a sad, weary sigh that echoed Mariana’s anguish far more eloquently than any words.

‘I can feel the strain it’s causing you,’ she said. ‘The need to be strong, for Zoe, for the college, for yourself—’

Mariana shook her head. ‘I don’t matter. But Zoe, and those girls … I’m so scared—’ Her eyes filled with tears. Ruth leaned forward and edged the box of tissues towards her. Mariana took a tissue and wiped her eyes. ‘Thanks, I’m sorry. I don’t even know why I’m crying.’

‘You’re crying because you feel powerless.’

Mariana nodded. ‘I do.’

‘But that’s not true. You know that, don’t you?’ Ruth gave her an encouraging nod. ‘You’re much more capable than you suppose. The college, after all, is just another group – with sickness at its core. If something of this nature – toxic, malignant, murderous – were operating within one of your groups …’

Ruth left the sentence hanging. Mariana pondered it.