Marty Greenwood wanted to own the spice trade of Mars, but he had never once seen the spice he meant to corner. He stood outside his weathered trading cabin, counting coins into a leather pouch. Every caravan on this red world carried redroot spice. Marty planned to buy it all, then sell it back at his price. One problem stopped him cold. He could not tell real redroot from a fake, and every seller knew it. A trader had cheated him last week. Marty had paid good silver for a sack of ground dust. He rubbed some on his tongue now and gagged. Sand and dried mud. He had been robbed, and he would be robbed again until he learned the truth of the spice. Marty needed an expert nose. He remembered a story from an old caravan driver. Redroot grew near the healing trees, and the small green creatures that fed there could smell it from far off. One such creature scratched at the base of a nearby tree, its three bright eyes fixed on the fruit above. Marty crept close with a berry in his palm. The green bunny sniffed, twitched, and hopped onto his boot. He fed it slowly and carried it back to his cabin porch. Then he opened a big communal chest where he kept his sample sacks. He set two open pouches before the bunny. One held the mud he had been sold. The other held a pinch he had begged from an honest old woman that morning. The bunny turned from the first pouch at once. It buried its nose in the second and licked the grains greedily. Marty grinned. Now he had his test. He filled the chest with a dozen mystery pouches, some real, some fake, gathered from stalls across the market. He held the bunny over each one. The creature sorted them cleanly. It refused the fakes and dove into the true redroot every time. By dusk Marty had five sacks of real spice and a nose he could trust. He locked the rest in the chest and latched the brass clasp tight. Word spread fast in a small market. A trader had come out to sell Marty another bag of dust. He watched the bunny reject it, snatched his sack, and hurried off. Marty laughed and slapped his knee. He could not be cheated anymore. That night a low growl woke him. He rushed to the porch. The chest lid hung open. The bunny was gone, and so were three of his best sacks. In the dirt he found paw prints too large for the little creature. A big green guard dog stood at the tree line, teeth bared, guarding the thief who had stolen his prize. Marty could now spot true spice. But someone else had learned he owned the only nose that could, and they wanted it for themselves.