Citadel of Lost Ships

It was a Gypsy world, built of space flotsam, peopled with the few free races of the Solar System. Roy Campbell, outcast prey of the Coalition, entered its depths to seek haven for the Kraylens of Venus—only to find that it had become a slave trap from which there was no escape.
Roy Campbell woke painfully. His body made a blind, instinctive lunge for the control panel, and it was only when his hands struck the smooth, hard mud of the wall that he realized he wasn't in his ship any longer, and that the Spaceguard wasn't chasing him, their guns hammering death.
He leaned against the wall, the perspiration thick on his heavy chest, his eyes wide and remembering. He could feel again, as though the running fight were still happening, the bucking of his sleek Fitz-Sothern beneath the calm control of his hands. He could remember the pencil rays lashing through the night, searching for him, seeking his life. He could recall the tiny prayer that lingered in his memory, as he fought so skillfully, so dangerously, to evade the relentless pursuer.
Then there was a hazy period, when a blasting cannon had twisted his ship like a wind-tossed leaf, and his head had smashed cruelly against the control panel. And then the slinking minutes when he had raced for safety—and then the sodden hours when sleep was the only thing in the Universe that he craved.
He sank back on the hide-frame cot with something between a laugh and a curse. He was sweating, and his wiry body twitched. He found a cigarette, lit it on the second try and sat still, listening to his heartbeats slow down.
He began to wonder, then, what had wakened him.
It was night, the deep indigo night of Venus. Beyond the open hut door, Campbell could see the liha -trees swaying a little in the hot, slow breeze. It seemed as though the whole night swayed, like a dark blue veil.
For a long time he didn't hear anything but the far-off screaming of some swamp-beast on the kill. Then, sharp and cruel against the blue silence, a drum began to beat.