"Take me to the Hotel de Mars," he told the driver. He leaned back comfortably, gloved hands resting on the head of his cane while he looked around him. A strange, glass-domed city, set in the heart of Mars' desert wastelands. A thriving city, with low buildings touching the glass roof of the dome. The rain-maker went on, the first drops splattering down from the overhead sprinkler system. Unterzuyder cringed. "Driver, driver!" he cried, rapping smartly with his cane. "Do you want me to catch my death?" The driver hurriedly caused the separate halves of the glassteel cupola to fold over the car. Unterzuyder settled back injuredly. * * * * * At the registration desk of the Hotel de Mars, he asked for, and was shown to the room of, Mr. Nathaniel and Miss Fayette Beecher. The door was thrown open by a tanned blonde girl in smart gray jodhpurs and slick boots. Her face at first registered a nervousness. Then it smoothed. "Oh!" she sang out, blue eyes widening and taking him in from head to toe. "You must be Mr. Straley." She cocked her lively face cutely to one side. "_Are_ you?" Unterzuyder's heart banged. He bit his lip. This was exactly the kind of girl his dead mother warned him to stay away from. Coquettish. Sexy. Treacherous, like most females. And he had lately noticed, to his dismay, that he, an Unterzuyder, was becoming far too susceptible to such unhealthy influences. "I am Mr. Straley," he said coldly. "Carruthers Straley, founder of Titan Settlers, Ltd. Shall I come in?" "Please _do_. For a moment, I lost my wits." She's making a play for me, like all females, he thought. Discouragedly, Unterzuyder went in. He sat down on a sponge-plastic chair, resting his gloved hands on his cane and looking upon the girl sternly. "Daddy!" she sang out. "Mr. Straley is here!" A man with a half-bald head and a deep tan lunged into the room carrying a heavy rocket-gun. His grin was wide, his voice reedy and enthusiastic. He was happy to know Mr. Straley. He laid the gun tenderly on the floor. Unterzuyder looked at it distrustfully. Beecher's reedy laugh sounded. "It's not cocked," he explained. "You caught me right in the middle of a clean-and-polish job. That ol' gun o' mine's been everywhere, mister. Most of the Moons of Jupiter, out on the deserts--even Africa. Yessir, our exploring expeditions have taken us into every corner of the Solar System that's available." The girl whipped open a drawer in the bottom of a boxy chair made of crystal glassteel. "And here's _my_ pet!" She reached in to pull out a long-snouted neutron gun with a triple trigger. Unterzuyder's heart banged for the third time in an hour. In the drawer was one other object: _Tertium Organum_, A Key To The Enigmas Of The World. An old book. A musty book. The book from his beloved dead father's library. The book that held the Unterzuyder map. His breath hissed. Beecher leaned solicitously forward. "Anything wrong, Mr. Straley?"