"A successful mission!" Morguma giggled. "Now we return to our lovely base to rest!" O'Dea and Hawthorne glowered. The next day was similar to the first, and the one after it, and all the rest until they had turned in a dozen days of work as slaves in the asteroid belt. O'Dea became proficient in operating his instruments; and Hawthorne brushed up on precision bombing until he could have planted his loads on a dime, if anybody had provided the dime. They found out that the Centaurs didn't believe in resting on the Sabbath. Working hours were roughly from sunup to sundown--about an eight hour stretch, since Avignon's day was shorter than Earth's. At dawn, a skipping troop of young Centaurs invaded their chambers. The students were learning English, diplomatic French, South Martian Portuguese, and a score of other languages of which Hawthorne and O'Dea knew nothing. Then Morguma came and led them to a huge boiler factory that was fitted as a dining room, where they toyed with Centaur food and ate vita-horm capsules salvaged from their ship. After that, it was out to the asteroid belt for another load of frozen atmosphere. "Oh, Hell," said O'Dea. They were going back to their quarters after another day's work. "If it wasn't for that picture of Mercedes, I'd throw in my buttons. I'm dying to see a human being again!" Hawthorne's homely face turned suspiciously to him. "I'm here, ain't I?" O'Dea raised an eyebrow and turned away. A fleet of powerful Centaur dreadnaughts was landing. They had just performed the fabulous task of transporting a huge frozen lake to Avignon--a miracle of coordination. O'Dea filled his lungs with air. He removed the blanket from his shoulders, let his chest rise and fall evenly. "Almost as good as Earth," he said. "This air is wonderful now, but it's wasted. Only two humans to breathe it--hey!" He stared at the spindly mountain that rose to a dizzy peak at the far end of the valley. A thin stream of smoke rose from it. "I never noticed that before. Morguma--is that a volcano?" Morguma, who had paused to watch them enjoy the air, looked toward the steaming mountain top and uncovered his fangs in a friendly smile. "Entirely without harm, my charming friends of Earth! Our great scientists have performed in full an investigation. There is absolutely no danger from that volcano!" O'Dea peered suspiciously at the distant cone. "If that thing ever goes off, this valley will be buried!" "Oh fear not that this luscious land will be demolished, my beautiful comrades! Not a hair of your lovely heads will be harmed!" Hawthorne growled. O'Dea made a fist of his right hand, rubbed it thoughtfully. But he shrugged, looking at the Centaur's twelve arms. They continued into the noisy dining room. As they entered, Hawthorne stopped short and glared. Suddenly shaking with anger, he waved his fist at Morguma. "This is the limit! You can kill me, but I don't have to stand for--this!"