Senses a sleep spell

I brought Mouse for a reason, too. Besides being a small moun tain of loyal muscle and ferocious fangs, Mouse could sense bad guys and dark magic when they were nearby. I had yet to encounter the creature that could sneak by Mouse unobserved, but just in case today was the day, I had the unguent as a backup plan.
I got off the elevator, and the hairs on the back of my neck immediately rose up. Mouse lifted his head sharply, looking back and forth down the hall. He'd felt what I had.
A fine cloud of magic hung over the entire floor.
I touched it carefully and found a suggestion of sleep - one of the classics, really. This one wasn't heavy, as such things go. I'd seen one sleep spell that flattened an entire ward of Cook County Hospital. I'd used another to protect Murphy's sanity, and it had kept her out for nearly two days.
This one wasn't like that. It was light, barely noticeable, and not at all threatening. It was delicate and fine enough to filter into homes even through their thresholds - most of which were weak enough: Apartments never seemed to have as much defense as a real, discrete home. If those other spells had been sleeping medication, this one would have been a glass of warm milk. Someone wanted the residents of the floor to be insensible enough not to notice something, but not so out as to be endangered should there be an emergency, like the building catching fire and burning down.
Don't look at me like that. It's a lot likelier than you'd think.
Anyway, the suggestion was another finely crafted spell: delicate, precise, subtle, much like the earlier veil Lasciel had spotted. Whoever or whatever was crafting these workings was a pro.


White Night Chapter 10, Page 103