"No, I suppose not," the Doctor replied. He took a few steps away from the TARDIS and his feet sank into the hot sand. There was nothing out there, nothing he could see, except---

"Wait, do you see that?" he asked, pointing out into the distance. "Sort of a cloud of dust."

A memory hit him, then. Standing on a sandy dune, looking out into the vast nothingness of a world of sand. If only he could remember why.