“Yes, thank you, Greg, and the pretty blue is why they call it Indigo Lake.” She gritted her teeth, “I meant this; focus, here.” She tapped the screen harder, over a section of sheer cliff wall. The granite and diorite batholith wall of Indigo Lake on Baranof Island was about eight hundred feet high, and even from the great distance, its edifice looked intimidating.

The image itself was nearly drained of color, and some aspects were highlighted. One being the lake, a deep blue, others were paler blues and grays, with dots of orange speckled around.

“It’s got a thermal overlay; what we’re looking for is hotspots. Anything that’s above air-temp normal.” She raised an eyebrow. “So, now, does anything look a little strange to you; maybe leap out?”

There were specks of warm yellow and orange dotted about, which most probably represented some larger wildlife like caribou, but there was a larger flare she knew caught his attention. He folded his arms, nodding. “Yep, there’s something hot on the wall.”

“Bingo.” She pointed, gun-like at his chest, and then turned back to the screen. “But not on the wall, instead, in the wall. There’s sure something hot in there. My bet is there’s a cave entrance that’s pushing out heat from somewhere below the lake.” She jiggled her eyebrows. “Maybe another lake.”

“Mineral springs. Hey, have you ever heard the legend of Bad Water? It’s supposed to be haunted.”

She scowled him to silence. “No, the whole area is called Bad Water by the locals, and not even they remember why. It’s not the lake.” She waved a hand. “And before you even say it, there’s no way some local wildlife is big enough to generate that much of a heat signature, and if something has flown in, it’d have to be the size of a damn ostrich.”

“Damn, I was just going to say ostrich.” He grinned. “So, a geothermal vent then. This area is still active, minimally, sure, but still. I know the geology, Cate. Plate tectonics in those parts are a huge generator of the wild Alaskan structures.” Greg unfolded his arms and made shapes in the air. “The North American Plate is still riding over the top of the Pacific Plate – the valleys are sinking and the mountains are growing taller at a rate of about an inch or more a year.” He smiled, looking self-satisfied.

“Bullshit,” Cate said over her shoulder.

He snorted. “Well, thank you for your professional rebuttal, your honor.”

“I mean, bullshit to it being just some sort of thermal vent. I think it’s a vent all right, but not leading to deep magma, or steam from super-heated rock, or even heat from subduction friction.” She turned to him. “I think it opens to a body of warm water.”

“Your mythical secret lake?”