‘Where did this take place?’

The boy looked embarrassed. ‘In the stairway outside his room. Not very wise of me, in retrospect.’

‘Which college was that?’ asked Holmes casually, as if he could not remember.

‘Trinity.’

‘Had you been there before?’ asked Holmes.

Vitale shook his head.

‘How did you find his room, then?’ I asked.

‘I knew it was Trinity, Great Court. I arrived with a large box of cakes and biscuits. The porter was happy to direct me.’

‘In the middle of the night?’ asked Holmes. ‘Where did you find those?’

‘I stole them. A student on my floor is always well provisioned by his parents.’

‘Then that student, at least, saw you?’

‘No, he was asleep when I took them. He heard nothing.’

Holmes stared at Vitale for a long moment. ‘You are holding something back, Mr Vitale. I might even say lying. May I suggest you be forthcoming?’

A noise behind us made all three of us turn to the door. Silhouetted in the doorway, the light behind him, was Cosimo Fortuny.

‘Leo!’ cried Fortuny. ‘What are you doing here? I gave you calculations to run and a report to write up.’ He glanced at Holmes and me. ‘Not these two again! I told you – no visitors!’

I could see the form of a woman hidden behind Fortuny. It appeared that the handsome young scientist had other plans in the laboratory that night.

‘Then who is with you, Cosimo?’ said Leo Vitale angrily. ‘There cannot be one rule for you and another for me!’ He waved towards the dangling tubes. ‘And what is all this nonsense?’

‘This is not a visitor, this is a donor to our research,’ said Fortuny irritably.

I grasped Holmes’s arm. ‘Holmes, shouldn’t we be leaving?’ I whispered.

But my friend’s face was frozen in surprise. I followed his gaze to the door. Cosimo Fortuny had entered, leaving us a clear view of his guest. It was none other than the flamboyant Madame Ilaria Borelli.

‘Madame!’ I exclaimed, gaping in astonishment at what I perceived to be an incomprehensible coincidence.

I turned to Holmes.

He stared at her, fascinated. A slow smile of understanding crossed his face. He nodded. ‘Madame Borelli, the research. Brava!’

CHAPTER 32

Lucifer’s Lights

‘It is Mr Holmes! And the doctor!’ exclaimed Madame Borelli. ‘What a pleasant surprise.’ She turned to Fortuny. ‘Cosimo, this man, Mr Holmes, he saved me when I was being accused of murder!’ She gave Fortuny’s arm a squeeze.

I could not fathom the nature of this coincidence. But my friend clearly did. He continued to nod in understanding.

‘I am on the trail of a great new illusion,’ she said, by way of explanation. ‘You are a detective of murder, Mr Holmes. I am a detective of magic. And I perceive the next great stage effect will come from this laboratory. With this man, Cosimo Fortuny.’