Dusty and tired, Lucy wheeled her Ducati back through the tunnels underneath the warehouse. Even with her broken helmet removed and hooked over one of the handlebars, this was a far from straightforward exercise. Her right hip ached abominably from where she’d crash-landed on it – by morning, she’d be bruised the entire length of that side of her body – and the bike was heavy. It hadn’t suffered anything more than superficial damage, and could easily be ridden, but she didn’t feel in a fit state. On top of all that, the route back wasn’t particularly easy to trace.

She’d hurtled through the network of passages so quickly that she’d barely had time to register landmarks. A couple of times she went the wrong way and had to double back, which was even more exhausting because it often meant manoeuvring the bike in a three-point turn halfway along corridors so cramped that there was minimal room.

It was a good fifteen minutes before she returned to the main undercroft. This place itself would have been difficult to identify, if it hadn’t been for the fresh air flowing in through the garage-sized entrance at the top of the concrete ramp. There was no longer any sign of Sister Cassie. Frustrated, Lucy climbed onto her bike, kicked it into life and rode it up and over the rubble barricade before mounting the ramp. When she reached the top and emerged onto Canning Crescent, she braked.

The ex-nun was seated on a nearby kerb. She’d replaced her wimple, veil and cloak, and was patiently rearranging the various bits of rubbish that had fallen out of her satchel.

‘There you are, child,’ she said, as Lucy trudged over. ‘Thank Heaven. I thought something bad might have happened to you. If only I had a phone, I could have alerted some of your colleagues.’

Lucy regarded her wearily. The ex-nun seemed to be unhurt. At least, no blows had left visible marks on her head or face. ‘Sister … don’t you think something like this was always likely to happen? The places you go, the people you interact with …’

Sister Cassie shrugged as she knotted the ends of the satchel’s broken strap. ‘On the mission, one must take the rough with the smooth, child. Besides, what am I, if not an addict myself, an outcast?’ She sighed. ‘It does happen. More than you might imagine. So long as we are alive at the end, all is well.’

‘How’d the bag get broken? Did they try to pinch it?’

‘Heavens, no. It was … well, it was me they tried to pinch.’

‘What exactly happened?