To Rebka, Paradox was the most enigmatic and intriguing of all Builder structures. The dark, spherical bubble, fifty kilometers across, permitted ready entry but on exit removed all memories, organic or inorganic. Computers emerged with no recording on any storage medium. Humans who had reached the interior returned with the minds of newborn infants.

Exploration efforts had finally been abandoned; but lately visitors to the region of Paradox had been reporting changes. The bubble was different in external appearance, and possibly in internal status. A new effort might succeed.

It was a dangerous mission, but Hans Rebka had been looking forward to it. He had volunteered, and he had been accepted as team leader.

And then the call had come, just one day before the descent into Paradox.

“An alternative assignment…” The voice was thin and whispering, reduced in frequency spectrum by its passage through the Bose communications network. ”… to the double-planet of Dobelle. You must leave without delay…”

The space-thinned voice sounded in no way imperious, but the command emanated from the highest government level of the Phemus Circle. And it was an assignment for Rebka alone; his companions would proceed to explore Paradox. At first it sounded like an honor, a privilege that he should be singled out in that way. But as the assignment was explained to him, Rebka’s confusion began.

He knew his talents. He was a doer and a fixer, and a damned good one. He could think on his feet and improvise solutions in real-time to tough problems; he was a typical product of his home world, Teufel.

“What sins must a man commit, in how many past lives, to be born on Teufel?” Half the spiral arm knew that saying.