The look on Matt’s face was as if he had just been handed two stone tablets from the top of the mountain. However, with Tom missing, Aimee was in no mood to hear about inexplicable disappearances. The scientist in her leaped at the vague but fantastical inferences he was drawing from the little data he had to work with.

“Matt, everything you have mentioned has, or will have, a scientific explanation.” Aimee saw Matt open his mouth and raise his finger to interject, but whether to apologise or debate she never knew as Takeda interrupted them both.

“Please. They’ve found something, you must all hurry.”

Alex kneeled down beside Tank who was examining something on the cave floor. “It’s Johnson’s gun. No rounds fired. No blood either, just a lot of skirmish marks and more dragging.” Tank looked at Alex with more anger than fear—it was a natural reaction; the team was as close as family. They all knew it was a deadly business they were in, but rated themselves as the best and looked forward to going head-to-head with any opponent. Johnson was one of their finest. So how did he get ambushed, disarmed and carried off? And how the hell did he get across the chasm by himself?

Tank went to hand the gun to Alex, but it stuck for a second. He held the barrel to his nose then offered it to Alex. He didn’t need to; Alex could smell it from ten paces back. “Phew, ammonia and it’s slimy,” Tank said more to himself than to Alex while wiping his hand on his leg.

Alex looked up at Tank’s brother. “Mike, go a hundred feet down the cave and hold your position. Report in when you get there and do not engage with anyone or anything.” Mike nodded, snapped off a quick “roger that,” and was gone.

The entire team had now crowded around Alex and Tank. Alex handed the gun to Aimee. “Dr. Weir, your opinion please.”

Aimee touched the substance with her gloved finger, held it up to her nose and sniffed. She also tested its consistency between her thumb and forefinger. “I can’t be a hundred percent sure being away from the lab, but I’d say this is ammonium chloride. But there’s something else—some sort of biological binder making it sticky that I can’t identify without further analysis. Dr. Silex . . .” Aimee held out the gun to Silex but he made no attempt to accept it.

“I’d say it’s probably an introduced contaminant. Maybe something the soldier brought with him and spilled.”

Alex ignored the scientist and turned to Monica Jennings. “Could this be a naturally occurring substance down here?”