‘You misunderstand me. If you managed to rake some exposed flesh with that nail, and we find it, it’ll be the first piece of physical evidence we actually have.’

The floor was already strewn with trash, and they weren’t sure where the main altercation had occurred. Lucy finally resorted to what she told Sister Cassie was a ‘pattern search’, whereby they divided the space up into an imaginary grid and worked their way from one section of it to the next, scrutinising each ultra-carefully – and it was this that paid the dividend.

‘Ah-ha!’ Triumphantly, Sister Cassie indicted a minuscule object at her feet.

It was indeed a human fingernail, blackened and chewed, but slimy and red on its concave side, particularly around the root, which had clearly been torn out.

Lucy ran up to her bike, took a pair of tweezers and a small plastic envelope from the under-seat storage and hurried back down. Once the nail was in the envelope, she sealed it. They held it up for a closer look. At the business end of the nail, which was jagged, dangled a single tiny thread of skin-like fibre.

‘This is going to our lab tonight,’ Lucy said. ‘And you need to come back to the station too.’

Sister Cassie thought about this. ‘I can meet you there at a time when it’s convenient …’

‘No, Sister – it’s convenient now.’ Lucy was firm. ‘I need a full statement from you, okay? Not just about this attack tonight, but about everything else that’s happened.’

The ex-nun looked doubtful. ‘It’s rather a long walk. And I was hoping to sleep …’

‘I’ll saddle you on my bike, don’t worry. You need to come back with me, anyway. So we can get that hand fixed up.’

For the first time all evening, the ex-nun looked genuinely horror-stricken.

‘Me! Ride a motorcycle? I doubt I’d have the courage.’

‘Sister, you’ve just fought off a violent attacker, who could be responsible for several abductions. Plus, you live here.’ Lucy made an exasperated gesture. ‘I’m pretty sure that if you look deep inside yourself, you’ll find the necessary courage.’

Sister Cassie looked unsure but accompanied Lucy up the ramp, the latter pushing her bike. As they reached the outside, the mobile buzzed in Lucy’s pocket. She was puzzled to see that the call was from her mother even though it was after one in the morning.

‘Yeah, Mum?’ She leaned the bike on its stand.

‘Lucy … are you at the hospital?’ Cora sounded tense and upset, which made the question all the more worrying.

‘No, I’m not,’ Lucy replied. ‘Mum, what’s—’

‘Then I’ll see you there. I’m guessing you know what’s happened?’

‘I don’t know anything. Look … are you okay?’

There was a brief, breathy silence. Lucy pictured her mother sitting in her little car, about to set off, possibly surprised by her daughter’s ignorance.