One winter night a man arrives at the Sallent in Santa Pau. Soon this newcomer is engaged as a tutor to Mar, a thirteen-year-old girl. Her family is the axis around which all lives in the valley of Ser revolve. "This girl will be lost," says her grandfather, a man who has the gift of water divining and of giving orders without opening his mouth. To know what it means to get lost, we will have to travel the paths that connect the houses and the experiences of the inhabitants of a valley from which everyone ends up fleeing and only the ones who couldn't leave remain. The stranger seeks out their buried stories like a diviner, in the veins of the water, and paints a portrait of the valley and its people, of the era and the country, of its myths and of itself.