Songwriter and folk revivalist Anne Briggs recorded this abandoned lover’s lament in 1971 as a hauntingly spare invocation of a pastoral Great Britain. This standout from Raise the Roof, the harmonizing Plant and Krauss’ first album in 14 years, expands the song’s musical frame as a way of distilling the calm of its loneliness. Over a strings-driven, keyboard-sparkled arrangement that recalls the psychedelic-era Beatles, Plant delivers a restrained and deeply emotional lead vocal with deft occasional support from Krauss. He is the fool on the hill, knowing his yearning is pointless but still laying out meals and mash notes for the one who will never return. This is heartache as a route to enlightenment.