After some false turns, we got down to the place Harry had seen in his dreams, and, wouldn't you just know it, the whole thing was a trap! Sure enough, Voldemort had known that he could get into Harry's mind, although how he managed to squeeze into such a narrow, tiny place is beyond me. He'd been sending Harry dreams for a while, all intended to bring him down here, into the heart of the Department of Mysteries, so that Harry could retrieve a prophecy orb from the thousands of such that are kept there. It seemed that only the people named in a prophecy could handle one safely without going mad.