Tyler Dupree had died one day in August, the long Equatorian August, two years ago, the long Equatorian years.

Diane had hiked with him up one of the steep, rolling ridges of the coast, for no other reason than to sit at its summit and watch the forest drop like a deep green broadcloth to the sea.

Neither of them was young; both had lived out most of their extended lives as Fourths. Lately Tyler complained from time to time of fatigue, but he had gone on seeing patients, mainly the young men who worked as breakers (their injuries could be horrendous) and the Minang villagers among whom she and Tyler had settled. Today he had said he felt fine, and he had insisted on the long hike—he called it "the closest thing to a vacation I'm likely to get." So Diane had gone with him, relishing the dimness beneath the trees and the brightness of the high meadows, but also vigilant, watching him.

The Fourth metabolism was powerful but finely balanced. It could be pushed hard, but like any other physical thing it had a breaking point. Age couldn't be indefinitely deferred because the treatment itself aged. When Fourths failed, they tended to fail all at once.

Which was how Tyler had failed.

She thought he might have known it was happening. That was why he had insisted on this hike. They came to a place he loved but seldom had time to visit, a broad swath of granite and mountain grass. They put out a blanket, and Diane opened her backpack and withdrew the treasures she had stored for this occasion: Australian wine, bread from the bakeries of Port Magellan, cold roast beef, things foreign to the Minang diet to which they had become accustomed. But Tyler wasn't hungry. He lay down on his back and pillowed his head against a bump of moss. He was thin these days, his skin was pale despite exposure to the sun, and he looked, Diane thought, almost elfin.

"I think I'll sleep," he said. And it was at that moment, in the August sunlight and surrounded by the smell of rock and water and black earth, that she had known he was dying.

Some atavistic part of her wanted to rescue him, to carry him down the mountain the way he had once carried her across much of the continental United States when she was mortally ill. But there was no cure; the Fourth treatment could be taken only once.

Time later for grief. She knelt beside him and stroked his head. She said, "Can I get you anything?" And he said, "I'm happy right here."

So she lay down beside him and held him in her arms as the afternoon waned. Much later, much too soon, the sun went down, and it was time to go home, but only Diane stood up.

I'm happy right here.