The sixteenth floor began in the heart of a dead city. Gray stone buildings lined narrow, winding cobblestone streets. The sky was a flat, oppressive charcoal color. There was no wind. The only sound was the constant, rhythmic scratching of thousands of claws against stone. The city of Hamelin was submerged in a sea of rats. These were not common rodents. They were demon beasts with elongated limbs, jagged teeth, and fur that dripped with a caustic, green ichor.

The thirty climbers stood in the central plaza, surrounded by four-story townhouses. Above their heads, the system windows flickered into existence.

「Floor 16: The Pied Piper’s Encore」

「Main Scenario: Pay the Piper’s Debt」

「Objective: Clear the infestation or pay the toll.」

「Clear Condition: Ensure the city is free of the Plague-Rats.」

「The Offer: The Piper will remove the swarm in exchange for one permanent sacrifice from the party.」

Standing atop the spire of the central cathedral was a man dressed in a coat of many colors. He held a long, silver flute to his lips. He did not play it yet. He looked down at the players with a thin, sharp smile.

"One life," the Piper’s voice carried through the plaza without the need for a breeze. "Give me one of your companions, and I will lead these vermin into the river. You will pass this floor without a single drop of blood on your armor. Refuse, and the city becomes your tomb."

The players huddled together. The veterans of the previous floors, including the spearman Gwon, gripped their weapons. Among the newcomers was a woman named Sora. She wore light leather armor and carried a staff tipped with a pulsating blue crystal. She was a known tactician who had cleared the lower floors by exploiting environmental traps.

"We don’t pay tolls," Gwon shouted up at the spire. "We clear the floor our way."

Sora stepped forward, her eyes scanning the streets. "Wait. Look at the numbers. There are tens of thousands of them. If we fight, we will be buried in seconds. The decay debuff from their ichor will melt our gear." She turned to the group. "I have a plan. We use the narrow alleys to funnel them. I can set up a vacuum barrier to suffocate the swarm without engaging them directly. We save our stamina and bypass the sacrifice."

Kang Min stood at the edge of the fountain. He looked at the rats. They were crawling over each other in heaps, but they were not attacking yet. They were waiting for the music.

He remembered this floor from the Old World. In his previous life, he had watched a large guild called the Iron Phalanx attempt Sora’s exact strategy. They had used high-level area-of-effect spells to incinerate the rats. They had cleared the streets in an hour. But when the rats died, the system did not announce a victory. It announced a massacre. The Iron Phalanx had unknowingly slaughtered the cursed children of the city. The guild members received the "Infant Slayer" title, which reduced their stats by fifty percent for the next ten floors. Most of them died before reaching the twentieth floor.

The rats were not monsters. They were the victims of the Piper’s first debt.

"Your plan will fail," Kang Min said.

Sora turned to him, her brow furrowed. "And why is that, Singularity? Do you have a better way to kill ten thousand beasts?"

"They aren’t beasts," Kang Min replied. He pointed his sword at a rat near the front of the swarm. The creature had pale, human-like eyes and five-fingered paws instead of claws. "Look at the bone structure. Look at the way they move. They aren’t trying to eat us. They are trying to reach out."

Gwon looked closer. He saw a rat wearing a small, tarnished silver ring around its tail—a ring that looked like a child’s trinket. The realization hit the veterans like a physical blow. The stakes shifted instantly. They couldn’t kill the rats, but the rats were currently a lethal threat due to the plague they carried.

"Then what do we do?" Gwon asked. "If we can’t kill them and we won’t sacrifice anyone, we’re stuck."

A player named Jace, a scout with trembling hands, looked at the Piper. "We should just give him someone. One person dies, and twenty-nine of us live. That’s the logical choice. Why are we risking a ’Calamity’ title for a bunch of NPCs?"

Jace lunged toward a lower-ranking mage, attempting to push her toward the center of the plaza to trigger the sacrifice.

Kang Min’s hand shot out. He grabbed Jace by the wrist and twisted. The sound of bone snapping was muffled by the scratching of the rats. He threw Jace toward the fountain.

"Anyone who tries to pay the toll dies by my hand first," Kang Min said.

The Piper began to play.

The melody was sharp and discordant. It vibrated through the stone of the buildings and into the teeth of the players. The Plague-Rats reacted instantly. They screeched and surged forward, a tidal wave of gray fur and green ichor. 𝒇𝒓𝒆𝒆𝙬𝒆𝒃𝓷𝒐𝓿𝙚𝙡.𝒄𝓸𝒎

"Defensive positions!" Sora yelled, her tactical instincts overriding her shock. "Non-lethal only! Use blunt force and knockbacks! Do not pierce the skin!"

The battle began in the plaza. It was a chaotic, high-stakes struggle. The players had to defend themselves against a relentless swarm without killing a single creature. The mages cast walls of wind and force. The warriors used the flats of their blades and their shields to shove the rats back.

The rats were small and agile. They climbed over shields and dropped from the balconies of the houses. Gwon swung his spear like a staff, batting dozens of rats away, but the green ichor sprayed onto his greaves. The metal began to hiss and smoke.

"My armor is melting!" Gwon grunted.

The Piper changed the tune. The music became faster. The rats grew more aggressive. They began to pile on top of each other, forming tall pillars of vermin that leaned over the players’ heads.

Kang Min realized he needed to act before the players lost their composure and started killing out of panic. He reached into his shadow.

"come forth!" he commanded.

The tiger beast emerged from the shadows. It stood three meters tall at the shoulder. Kang Min did not give the order to hunt.

The Blue Tiger let out a resonant, low-frequency growl that countered the Piper’s flute. Blue mana poured from the tiger’s fur, expanding into a translucent dome that covered the players. The rats slammed into the dome but couldn’t pass. The tiger’s mana was a physical barrier that prevented contact without causing harm to the creatures.

"You’re holding them back," Sora said, her eyes wide as she watched the tiger. "But the tiger’s mana will run out. We need to stop the music."

"The flute is the anchor," Kang Min said.

’In the Old World, the Piper’s flute was protected by a sonic barrier.

You couldn’t get within ten meters of him without your internal organs rupturing from the vibration.’

He looked at Sora.

"Use your vacuum orbs. Not on the rats. On the Piper."