"Why are you doing this?"

Mackerel mumbled even with his mouth covered. Uijae raised his index finger to his lips, signaling for silence. The closer they got to their destination underground, the louder the noises became. How could he not hear that? Uijae quietly asked.

“Can’t you hear it?”

“…Huh?”

“Listen closely. Don’t you hear it?”

Mackerel lowered his eyes and tilted his head as if listening carefully. Soon, his face stiffened. He frowned slightly as he looked at Uijae.

“This sound…”