I'm trying to locate a short story about humans in the far future who have achieved immortality through scientific means.
The story opens with a tour group being led by a man who died and was brought back years later. He's an object of pity and curiosity, because his resurrection was botched, leaving him with a disability. He leads several people on a punishing hike, and at the end, only one couple remain, becoming physically reduced to smaller and smaller bits. I think eventually they opt to be restored. The point seemed to be that after living an extremely long time (a million years?), they had experienced so many things that the experience of suffering and dissolution was the only novel experience left to them.
It might be by Alastair Reynolds.
Does anyone know what this is?