A misty white void filled with starry specks numerous beyond imagining. Speculation: Perhaps some kind of cold storage space for the Returned or the Dreamers.
Thus far only Salinger and Peach have had any inkling of it.
When a number of people disappeared at once in a flash of light, Peach noticed pinpricks of light in the white flash and realized there was a depth to it, like motes of dust in a sunbeam. It almost seemed to make an image or a pattern for a moment.