dangerous, but not to it. Animal blood may as well be salt water as far as the Vyrus is concerned.

I feel a slight shifting of the air. The door I've left open is drawing the warmer air up and out of the school. I follow the draft backward and find the stairwell. I descend three flights to the ground floor, sniffing at the thin trail of air wafting up past me, picking out details from the last twenty-four hours. I can smell the decay of the zombies, the urine of Ali Singh, the nameless blood and brains of the other boy. I can smell my own slightly feral scent and the Ivory soap I use in the shower. Fresher than the rest is a heavy overlay of sweaty cop, coffee and fingerprint powder, and the excited tang of news reporters. Under it all, the heavy, damp rot of the building.

I retrace my steps to the room where the killing took place. The door has no lock, but the cops have sealed it with the inevitable yellow tape, the era's icon for tragedy. I tear it off and open the door. It reeks inside.

Normally in these things someone would have been here by now with a bucket of bleach to get things sterile, but I guess the cops want to leave the crime scene intact until they have a confession out of Singh. Result: taped body outlines, dried blood, dried urine, dried vomit from whoever found the slaughterhouse, and oh yeah, dried brains.

I pick out the zombie smell from the others and walk slowly around the room separating the scent into three distinct strands. There's the girl's musky undertone, the rank underarm stink of the one whose neck I snapped, and the hair product used by the guy I stepped on. Now that I have the zombie smell isolated into the three individuals I know of, I sniff for any other signatures hiding in the mix. It's not there. No sign of another zombie, the carrier.

But the girl's musk.