Delays came first, then death, then destruction. Nothing was left of the fleet, except a rotting mass of ruined hulks that would remain in their positions unchanged by time and unaffected by the worlds around them. The odd visitor who came over the next tens of centuries could not perceive what had happened, but only that something great had passed away here, like a crumbling heap slowly disappearing into the sands, great monuments laid to rest and forgotten, with only the barest, elusive hint of what it all once was. The rusting masses of metal, huge even from millions of kilometers away, had once been ships that could have used the entire resources of a planet to build. Combined with the guardians lurking in the shadows of the region, guarding treasures one could only dream about, forestalling travelers was a simple task. Even the great cruisers of old, though silent, had weapons that bespoke their once exalted status as the kings of the galaxy. Archaeologists implored their governments to give military ships over to the task of protecting them while they hastened to uncover ancient artifacts before their cloak of military impunity wore off and the guardians of the Graveyard began to overwhelm their escorts. Never did they find the merest utterance of the cause of this civilization's immolation, nor any sign of retribution to those who immolated.
One tale recalls those who unwittingly disturbed the resting place of some guardians of the crypt, the true virtuosos of the science and yet knowing nothing of the lengths to which ancient peoples will go to avenge themselves on people who have never heard of them, people far in the future who would give their kind immortality, in a sense, but all they got was death.
Six light frigates accompanied the research ships to the site, a true palazzo for the area. By all sightings it appeared to be a massive carrier, and thus a prime target as the docking bay doors were jammed open. For what reason no one could ascertain.
A detachment of marines accompanied the nervous scientists; after the fashion of marines, they made jokes about how ghosts didn't exist and how lucky they were to be put on this easy assignment. But there was something about these spotless, yet lightless halls that disturbed the imagination. On the bridge, where they entered, a green rheum covered the bridge windows. No one bothered to clean those, at least. The archaeologists made notes promiscuously, recording every single detail about even the control wiring and ventilation ducts.
Naturally the marines were seen as ignoramuses who could not tell the difference between an ancient artifact and a football, yet in the forward cargo hold it was a marine who discovered a rusted metal bar, which turned out to be some sort of message disk. The rust came off easily, and then a port was found in a wall. The disk was inserted, and a shivering electronic beep ran through and reverberated against every surface.
It was an hour before a frigate was able to evacuate the two survivors before the doors clanged shut, trapping the other bodies in there for millennia. A mortal has yet to disturb them, and the survivors warn against it, claiming they had been accosted by "shadow's shadows." The Graveyard is full of secrets. None should be disturbed, against the threat of death.