Marcus Spore had built an app that could map every fungal network in Quillmaw, and it was useless. The app needed spores from one rare mushroom strain to run. In three years, Marcus had never found a single one. He sat in his rented workshop, phone open to the dead screen, staring at a promise he couldn't keep. He had money left for maybe two more months. After that, the workshop was gone. So Marcus went to the one person who might know where the strain grew. Dr. Moss Underwood was a mycologist who had not spoken to anyone in the valley for years. People said the doctor answered no knocks. Marcus knocked anyway. The door opened on a small, gray-haired figure in a mud-brown jacket. Round glasses slid down a red nose. Dr. Underwood looked at Marcus the way you look at a fly in your soup. "You're the app man," Dr. Underwood said. "I don't help app men." Marcus put his boot in the door. "I need one strain. You know the ground here better than anyone alive." Dr. Underwood snorted. "Everyone wants my ground." But the doctor's eyes flicked past Marcus, down toward the hillside. That flick told Marcus more than any answer. "Show me," Marcus said. "I'll trade you the map when it's done. Every network. Free." Dr. Underwood went still. For a long moment the only sound was wind in the pines. Then the doctor grabbed a walking stick and pushed past him. "You'll ruin your knees," Dr. Underwood said. "Follow anyway." They climbed for an hour. The doctor moved fast for someone so small, stopping only to touch bark and sniff the air. Marcus slipped twice on wet leaves. His lungs burned. He did not complain. Then Dr. Underwood stopped at a fallen log and pointed the stick. "There," the doctor said. Marcus knelt. A dense cluster of shaggy white mushrooms spilled over the rotten wood. Soft tendrils hung down like frozen rain. His hands shook as he touched one. He had studied a thousand photos. This was the strain. This was the thing his whole app had been waiting for. "Take a small piece," Dr. Underwood warned. "Only one. The rest stays." Marcus cut a single cluster free and sealed it in a jar. Through the glass, the white tendrils glowed faint in the shade. He had it. After three years, he finally had it. Then the doctor spoke again, quiet now. "You'll want to grow it," Dr. Underwood said. "You can't. Not here. This strain only fruits underground, in the dark, in a sealed room. Get the air wrong and it dies in a day." Marcus looked at the jar. He had spent everything to find the mushroom. He had nothing left to build the room it needed to survive. "Where do I even get a place like that?" he asked. Dr. Underwood started back down the hill. "That," the doctor said, "is your problem now."