Femke leads us out of her office, down an ancient elevator to the basement of the building. I smell the revenants before the door opens, catching their scent even as I step through the doors to descend. The scent grows stronger as we plunge underground and I can barely stand it by the time the elevator doors swish open.

I have to breathe through my mouth, almost panting from the effect of the stench. Piers quickly offers me a handkerchief, ...