Juan hadn’t taken a breath in almost a minute, and his vision was narrowing to a central point surrounded by gray, but he had just enough mental capacity to unhook the air line going into his helmet and replace it with one from the fresh tank. Fifteen seconds passed and nothing happened, he still wasn’t getting air. Then for some reason Little Geek barreled into him again.

Max was trying to tell him something. What was it? He didn’t know and just wanted to go back to sleep. His head sagged, and for a third time the ROV bounced off his chest. It pirouetted so the bulky trimix tank was right in front of him.

The valve. Juan reached out a hand and cranked open the valve. With a life-giving hiss, his helmet filled with breathable air, and he took it so deep into his lungs, they felt like they would burst. His confusion began to clear as his oxygen-starved brain rebooted. He took ten, twenty deep breaths, giddy at the feeling and never so thankful. He flashed a diver’s OK sign at the camera mounted below the lights. In response, Little Geek spun three hundred sixty degrees, like a happy puppy circling after its tail.

Little Geek settled onto the ground next to him as if it wanted to be petted. It was then Juan saw the bundle Max had secured to the top of the ROV. He opened it and said a silent prayer of thanksgiving. Hanley thought of everything. His hands were numb to the point of uselessness, and he could barely guide a finger through the activation ring of a magnesium flare, but he managed.

The light was blinding white and would have scarred his retinas if he’d looked at it, but his head was turned away. He didn’t care about the light the flare threw off, only about the way it heated the water there in the lee of the mine tender’s boiler. He could feel the difference after only a few seconds. Also stuffed in the bag were chemical heat packets. He broke their seals to activate them and clamped them between his thighs and under his arms. Others he stuffed between his dry suit and buoyancy compensator directly over his heart.

He gave himself ten minutes to recover. By the time he was ready to go, the acrylic-domed Discovery 1000 with Eric Stone at the controls had joined him. Eric and Little Geek stayed with him during the mind-numbingly long ascent, hovering nearby as he went through hours-long decompression stops. Despite the cold and his exhaustion, he took it slow and safe. He knew he’d probably have to sleep in the Oregon’s cramped decompression tank with Mike, but one night was all he was willing to put in.