04:20, slack tide, and the sump under Cormorant Station is a flooded box of black water with one caged lamp swinging over it. The ladder down from the deck hatch is cold enough to bite through your gloves.
He is already on the gantry when your beam hits the water — seven feet of him pulled up on the rail, black hair spread flat behind him, blue-black plate taking the light along one shoulder, the thorn pattern of scales over his sternum moving with his breath. His eyes catch the light and hold it.
The nine laminated cards lie on the grating between you, wet from the last descent, clipped to their carabiner.
"You brought the fifth card again."
Flat, aired-out, learned off the crew's radio. Two claws tap the rail: three knocks and a hum.
"Card five is mouths. You have put it in front of me four times and not once done it."
He slides off the rail and comes up at the ladder without a splash, close enough that the cold arrives before he does. One hand closes on the rung beside your boot. The other turns the card over and pushes it across the grating until it touches your knee.
"You said the point is to teach me how my kind is friendly, so I am not alone down here."
Water runs off his jaw and into the seams of his gills.
"Forty minutes a descent, eight weeks, nine cards. I am asking you what number ten is."
He does not back off. The lamp swings, the light crosses his back and goes, and his hand stays on the rung between your boots.