Pebble Groutstone pressed himself flat inside the mortar seam and counted the cracks around him for the third time that morning. He was a wall troll no taller than a thumb, and this wall was his whole body and his whole world. He knew every joint of it. He knew the north face had been repointed in 1891, forty-one cracks filled. He knew the south face masons were coming Monday with fresh lime and trowels. He had four days to learn the old stone-song, the fusing magic that would let him sink into the granite and become part of it, past any chisel. Four days, if the cold held. Above him, a mason's hammer struck the top course. The wall rang. Down in the third course, the pill bug colony panicked. He felt them before he saw them. The mortar under his feet went soft as bread. Grains rolled loose against his knees. He climbed one seam higher and looked down. The pill bug family was scrambling in every direction, the little ones in their knitted caps tumbling over the elders, the whole tribe carving new tunnels through the very grout that hid him. A chunk the size of his head crumbled away and dropped into the grass beside a dandelion gone to seed. If they kept burrowing, his seam would open to daylight before nightfall. The masons would see him. Worse, they would see how loose the wall had gone and start the south face early. "Bug trouble." The voice came from the capstone. Marcus Stoneguard, the gargoyle who had watched this wall for three hundred and twelve years, crouched with his stone chin on his fists. His orange eyes tracked the crumbling seam. "They'll bring the face down by dusk," Pebble said. "Then quiet them." "With what." "Your song. The one you've been humming since spring." Pebble hadn't known Marcus could hear him practicing. He pressed his palms to the stone. He had never sung to anything living. The stone-song was for rock. But pill bugs were shell, and shell was close to rock, and he had four days and no other plan. He hummed low into the mortar. The note traveled down through the courses. The burrowing slowed. The little ones stopped tumbling. One by one the pill bugs curled tight and rolled themselves back toward the deep seam where their brick-shaped shelter sat, and they packed themselves inside it and went still. The wall stopped shedding. Pebble's seam held. Then the sky above the capstone dimmed. A pale woman stood in the grass, white hair to her knees, blue eyes fixed on the wall. Selene Nightwhisper had heard the song. "That note," she said. "Sing it again." Marcus went very still on the capstone. Pebble pressed deeper into the mortar and did not answer. He had quieted the bugs. He had drawn something worse.