The Compact had known death, of course. Baselines who came to them too late for treatment. Injuries from accidents during construction. But they had not yet experienced death among their own.
Until Anya returned.
The UN observer who had visited years before came back, not as an observer, but as a refugee. The cancer they had pushed into remission had returned, aggressively. And she brought her husband's ashes in a simple urn.
"I need sanctuary," she told Kael, her once-proud posture bent with pain. "Not for healing. For... for witnessing."
She had been expelled from the UN for "collaboration." The Ephemeral League had labeled her a traitor to humanity. Her children, fearing for their careers, had distanced themselves.
"You gave us five extra years," she said, holding the urn. "Five years of love. Now I have months, maybe weeks. I don't want to die among people who call that love a sin."
They gave her a room overlooking the Skywell forest. Elara, now seven, visited daily. They would sit together, Anya in a chair, Elara on the floor, drawing or reading.
"You're not afraid of me?" Anya asked once.
"Of what?" Elara didn't look up from her drawing—a detailed sketch of the forest's canopy.
"Of death. Of... this." Anya gestured at her own wasting body.
Elara considered. "Everything changes. Cells change. Thoughts change. Why is changing from alive to dead more scary than changing from child to adult?"
Anya laughed, a wheezing, painful sound. "When you're older, you'll understand."
"I might be older than you soon," Elara said matter-of-factly. "In lived years, I mean. Not body years."
The truth of it settled between them. Elara, at seven, had the cognitive maturity of an adolescent. In a decade, she might think like a thirty-year-old while looking like a teenager. In fifty years...
"You'll watch so many people die," Anya said softly.
"I'll remember them," Elara said. "That's what Papa says we do. We become libraries of people."
As Anya weakened, the Compact faced a new question: How do immortals mourn?
They had no rituals for death. No traditions. So they created one. Each day, someone would sit with Anya and share a memory—not of her, but of someone they had lost. Thomas spoke of his daughter Chloe. Erika of her parents in Stockholm. Pierre of the friends who had rejected him.
Anya listened, growing weaker, but her eyes bright. "You're giving me companions for the journey," she whispered.
On the last day, she asked for Kael and Elara.
"I want to give you something," she told Kael. "Not knowledge. A question." She took his hand, her grip frighteningly light. "When you've lived three hundred years, and everyone you knew is gone, and the world has changed beyond recognition... what will keep you human?"
Kael had no answer.
She turned to Elara. "For you, a different question. You're the bridge. But bridges get walked on from both sides. How will you keep from breaking?"
Elara, serious, said, "By remembering why people need to cross."
Anya smiled. "Good answer." She closed her eyes. "The light here is beautiful. Like underwater."
She died that evening, as the artificial sunset in the Skywell cast long shadows through the forest.
They held the funeral in the Heartstone. Anya's ashes were placed in a niche in the stone wall, beside a plaque with her name and dates. But also, following her wishes, with a data chip containing her memories—not just of her life, but of the stories she had collected during her visit.
"This is our first death," Kael said to the gathered Compact. "But not our last. We will remember Anya. We will remember everyone who journeys with us for a while and then continues on. This is our compact with time: to carry forward what matters."
Afterward, Elara asked Lin, "Will we all have niches in the wall?"
"Those who want to," Lin said.
"I don't think I want one," Elara said. "I think I want to be a tree in the forest. So I can keep growing even after."
That night, Kael lay awake, Anya's question echoing. What will keep you human? He rose and walked to the nursery levels, where the youngest Longevo and Bridge-Born children slept. He watched them—eight children now, including three Bridge-Born born to other pairings. They were the future. Not just of the Compact, but perhaps of Earth.
He realized then: It wasn't memory that would keep him human. It was responsibility. To these children. To the world they would inherit. To the fragile, mortal beings who would live and die in the blink of his extended eye.