It was Alexander who suggested going back to the pond.
They were lying on the rocks by the lagoon after a morning of diving, drying off in the sun. Jason had just stayed down for a little over three minutes, his longest yet, and Alexander had spent most of those three minutes floating above him and pulling faces through the water.
"You could do it now," Alexander said. "The tunnel. The one you told me about."
Jason didn't answer right away.
He had told Alexander about the chamber under the pond in pieces, over many nights, the same way he had told him everything else. He had told him about the footprints, and the first failed dive with the rope going taut in the dark, and the panic that had nearly drowned him. And he had told him about the second time, years later, when he had stopped caring about much of anything, and had swum through to the chamber on the other side and found the mask.
"I did it before," he said finally.
"You did it once, when you'd stopped caring whether you came back." Alexander propped himself up on one elbow. "I'm talking about doing it properly. With a rope, and someone on the other end of it, and air in your lungs that you actually intend to use."
"Why?"
"Because it's there." Alexander shrugged. "Because we've been over every other part of this island, and that's the only place we've never looked. And because," he added more quietly, "I think you should see it again as someone who wants to be alive."
Jason looked at the sky for a long time.
"Tomorrow," he said.
* * *
They went in the morning, when the light through the grotto's cracks was strongest.
Alexander had made a new rope for the occasion, twice as long as the old vine one and braided from bark fibers and strips of cloth, and he tied one end around a spur of rock at the edge of the pond with a knot that Jason now knew by name. The other end he tied around Jason's waist, and then, after a moment's thought, a second loop around his own.
"You go first," he said. "You know the way. I'll be right behind you. If you stop, I'll feel it. If you pull twice, we both come back."
The pond looked exactly as it always had, black and still in the center of the grotto. Jason sat on the stone lip with his legs in the water. The cold climbed up through his feet into his shins, the same deep mineral cold he remembered, and for a moment he was back on the thirtieth morning, alone, with the rope going tight in the dark and the tunnel closing around him.
His heart started to race.
"Breathe," Alexander said beside him. "Slowly. From the bottom up. You know how."
Jason breathed. In, deep, holding it, and out again, long and slow. He did it five times, and on the fifth, the racing in his chest had eased into something steadier.
He slid into the water.
It closed over his head, cold and green and then gray, and he found the rock wall with his hands and pulled himself down along it. He knew the way. His body remembered it even though he had only swum it once, half-mad with grief and fury. One meter, two, three, into the dark. He felt the pressure build behind his ruined eye and let it build. He felt the faint current against his face, the island breathing out, and found the edge of the tunnel mouth with his fingers.
Behind him, the rope tugged once, gently. Alexander was there.
He went in.
The darkness closed around him, and the rock brushed his shoulders on both sides, and the old fear rose up in him like a wave. But this time he let it come and let it pass, the way Alexander had taught him. He counted his pulls. He kept one hand on the wall. And every few seconds, the rope around his waist tugged gently from behind, a small, steady reminder that he wasn't alone in the dark.
The tunnel bent downward, then leveled out. Somewhere around the place where the old vine rope had run out, he realized he was still calm, and nearly laughed, and lost a mouthful of air for it.
Then his hand struck open water, and he kicked upward toward the faint gray light, and broke the surface into air.
A moment later, Alexander came up beside him, gasping and grinning.
"Gods," he said. "That's longer than you said."
"I was a bit distracted the first time."
They hauled themselves out onto the stone and sat there for a while, breathing, water streaming off them onto the worn floor.
* * *
The chamber was the way Jason remembered it, and also completely different.
The first time, he had seen it through a haze of rage and exhaustion, and had looked at nothing but the mask. Now he looked at everything. The walls were not natural rock. They had been cut, and cut well, into smooth faces that met at clean angles, though the edges had been softened by time and the damp had left long dark stains down them. Thin cracks high in the ceiling let in narrow shafts of daylight, which fell across the floor in pale, dusty bars. Water ran in shallow channels along the base of the walls and vanished somewhere below.
And the air was fresh. Old and cool and still, but good to breathe.
"There's air coming in from somewhere," Jason said, looking up at the cracks. "It must go all the way up through the rock."
Alexander was standing by the pedestal in the center of the room. It was a simple block of the same cut stone, waist high, with a shallow hollow on its top, and it was empty.
"This is where you found it?"
"Yes."
Alexander ran his fingertips around the edge of the hollow without touching the inside, and took his hand away quickly.
"There's another way out," Jason said.
He hadn't noticed it the first time. In one corner, half-hidden behind the angle of the wall, was a low opening, a passage just high enough to walk through bent over. He crossed to it, ducked his head, and went through, and Alexander followed a few steps behind.
The passage ran for a dozen paces and opened into a second room, longer and narrower than the first.
Its walls were lined with niches.
They were cut into the stone in two neat rows, one above the other, running the length of the room on both sides. Each one was long and shallow, about the length of a man lying down. There were perhaps twenty of them. A thin shaft of light from somewhere above fell across the floor and lit the nearest ones.
They were all empty.
Jason walked slowly down the length of the room. He had seen pictures of places like this once, in a history textbook, and he knew what they were for. But in the pictures there had always been something left: bones, or scraps of cloth, or at least the dust of what had once been there. Here there was nothing. The niches were as clean as if they had been cut yesterday and never used.
"It's a tomb," Alexander said behind him. His voice sounded strange in the narrow space. "Isn't it? It's a tomb with no dead in it."
"Maybe they were moved."
"Maybe." Alexander didn't sound convinced. He had stopped just inside the doorway, and he hadn't come any further. "Or maybe they're not here yet."
Jason turned to look at him. In the dim light, Alexander's face was pale, and he was rubbing his arms as if he were cold.
"You're thinking about the story," Jason said. "The black shore."
"I'm not thinking about anything." Alexander looked back toward the passage. "I'd just like to go now, if you don't mind."
Jason looked around the room one last time. There were dark corners at the far end where the light didn't reach, and he could see what might be another opening in the back wall, but he felt it too now: a slow, crawling unease at the back of his neck, the sense of standing in a room that had been built for someone and was still waiting for them to arrive.
"Yeah," he said. "Let's go."
* * *
They swam back without speaking and climbed out of the pond into the familiar gray light of the grotto. Outside, the sun was high and hot, and the sea was bright and ordinary, and the unease faded a little with every step they took along the beach toward the cave.
But it didn't fade completely, and Jason noticed that Alexander didn't talk much for the rest of the day.
That evening, after they had eaten, Jason looked up from the chessboard in the sand and found that Alexander wasn't watching the game.
He was looking past Jason's shoulder, into the shadows at the back of the cave, where the white mask lay on its ledge of stone. The firelight didn't quite reach it. Its narrow eyes stared up at the ceiling, and its surface was as clean and pale as the day Jason had lifted it from the pedestal they had just seen, empty, in the dark beneath the island.
Alexander looked at it for a long time.
"Your move," Jason said.
Alexander blinked, and looked down at the board, and moved a piece without really seeing it. But a little while later, Jason glanced up again, and Alexander was still watching the mask.