Sterre spends her days at a microscope in the Rijksmuseum, arresting decay in seventeenth-century masterpieces. Freeze the crack. Keep the original. Never let anything change. It is a creed, and it has quietly become her life.

Then her husband dies, and a year later, at three in the morning, she asks an AI the question she cannot say aloud: is there any way to make a person live forever? The machine gives her history's strangest answer. On an island in Japan, a ninth-century saint is believed to have never died, and the pilgrims who walk his circuit of eighty-eight temples wear the words two walking together, because none of them, living or dead, walks alone.

So she goes. Fourteen hundred kilometers on foot, through mountain gauntlets and empty coasts, typhoon and heat, carrying a hidden scar and a daughter's unanswered messages. The road gives her people instead of answers: an Australian who hides nothing, an Osaka accountant with no patience for the mystical, an old woman whose kindness cannot be repaid, and a Glaswegian veteran on his fifth lap around the island who may be a warning, a mirror, or something stranger.

Told in part by Enheduanna, the first author in human history, a woman who has had four thousand years to think about what immortality costs, Walk Together is a novel about grief, repair, and the oldest question there is, answered the only way it has ever been answered: by what we give away.