A speaker mourns someone who has died, and the poem moves from tenderness to a strange, quiet bewilderment. It opens with a soft address, "Gentle sweet," then pictures the dead person already "halfway across the void," travelling away into the night. The distance feels huge and still growing.
The middle turns a familiar idea around. We usually worry that the living will forget the dead, but the speaker says the real problem is that the dead forget the living. That suggests the loneliness of being left behind: the one who has gone no longer thinks of us, and the connection runs only one way.
The final lines are the most striking. At the grave, the speaker feels certain of just one thing, that the person is nowhere else but not here. The grave offers no comfort. The mood is hushed, bare, and quietly aching, with grief that has lost even its usual place to go.