The Weeping Mother was a problem David could not solve with force.

  Even if the Shadow Bear Spirit could match her in raw output—which was not guaranteed—a fight in this corridor would produce noise far above any safe threshold. The true conductor, the quasi-S-rank root process with the iron mask, would be summoned by the disturbance. Two boss-tier entities simultaneously was not a survival scenario; it was arithmetic with a negative answer.

  So: not force. Logic.

  David’s eyes were closed. He was standing in the shadow of a doorframe in Car 12, ten meters from the red iron door of Car 13, running through the dungeon’s rule set in his head like a programmer reviewing an API specification for exploitable edge cases.

  The door to Car 13 was locked by an absolute restriction. The Master Key explicitly could not open it. The System had stated this as a hard constraint—not a difficulty rating, not a challenge to be overcome with sufficient power, but a logical impossibility: this key does not fit this lock.

  But rules were code. And code, no matter how carefully written, contained assumptions. And assumptions could be violated.

  David opened his eyes and recalled Rule 10:

  Rule 10: There is no dining car on this train. If someone invites you to "Dining Car No. 13," politely decline.

  He read it again in his mind. Then a third time. Then he began to disassemble it.

  The rule had two components. Component A: there is no dining car. Component B: if someone invites you, decline.

  Component B was the interesting one. It presupposed a scenario in which an invitation to Car 13 could be issued. For an invitation to be valid, the destination must be accessible—you cannot invite someone to a room that cannot be entered. If the door is permanently, absolutely locked, the concept of "invitation" is logically incoherent, and the rule’s instruction to "decline" is meaningless.

  But the rule existed. The System had written it. The System did not write meaningless rules—every rule David had encountered served a functional purpose within the dungeon’s logic. Therefore, the invitation scenario was possible. Therefore, the door could be unlocked. And the unlock condition was the invitation itself.

  It was a dependency injection. The door’s lock state was not controlled by a physical key but by a logical precondition: the existence of a valid invitation event. Create the event, and the system would be forced to set the door state to "unlockable"—because failing to do so would create a paradox that violated its own rule set.

  David smiled. It was not a warm smile. It was the smile of a programmer who had found a race condition in a production system and was about to exploit it.

  He needed an entity to issue the invitation. Any entity with the authority to reference Car 13 as a destination would do.

  True Sight swept the corridor. Two cars back, in a maintenance closet in Car 10, a low-tier cleaner entity was hiding—a janitor-class process, bottom of the hierarchy, carrying a mop and a bucket of something that was definitely not water. It had been avoiding the Weeping Mother’s patrol, same as David.

  Enjoying this book? Seek out the original to ensure the author gets credit.

  Perfect.

  David moved back down the corridor in silence. Three minutes later, he had the cleaner pinned against the maintenance closet wall, the Shadow Bear Spirit’s jaws locked around its neck, his combat knife pressed against the space where a human’s carotid artery would be.

  The cleaner made a strangled, gurgling sound of terror. It understood the hierarchy instantly: it was outranked, outgunned, and entirely at the mercy of something that had none.

  "You’re going to do exactly one thing for me," David whispered. "You’re going to say the following words, exactly as I tell you: ‘Honorable passenger, I invite you to dine in Car 13.’ Get it right and I’ll let you live. Get it wrong and the bear eats you."

  The cleaner’s eyes—small, yellow, rheumy—darted between David and the Bear Spirit. It was calculating survival probabilities. The calculation did not take long.

  David carried the entity to the Car 12 corridor, positioning them five meters from the red door—outside the Weeping Mother’s immediate aggression radius but close enough for the invitation’s logical effect to propagate.

  "Now," David said.

  The cleaner spoke. Its voice was thin, leaking, the words forced through a throat that was being gently compressed by a shadow-bear’s claws:

  "Honorable passenger... I... invite you... to dine... in Car 13..."

  For a fraction of a second, nothing happened.

  Then the train’s logic engine caught the paradox.

  David felt it before he heard it—a vibration in the substrate of the dungeon itself, as if the rendering engine had stuttered while processing a conditional that returned a value it hadn’t been built to handle. The air pressure changed. The fluorescent lights in the corridor brightened, dimmed, brightened again.

  CLUNK.

  The red iron door’s lock disengaged. Not smoothly—violently, as if the mechanism was being forced open by the system’s own internal logic correcting for the paradox David had manufactured. The door shuddered, groaned, and began to slide open.

  From inside: the smell of blood, machinery, and something else—the high, thin cry of an infant, small and furious and alive.

  The Weeping Mother heard it.

  Her entire body locked rigid. The broken fingernails stopped scratching the metal. Her milk-white eyes, which had been scanning the corridor with their endless, desperate search pattern, fixed on the opening door with a focus so intense it was almost visible—a beam of concentrated maternal fury cutting through the darkness.

  "My... baby..."

  The transformation was instantaneous. Her belly—hollow, empty, maintained in its distended shape by nothing but grief and rage—split open. Not to release a child, but to deploy weapons. Black tentacles, dozens of them, each one tipped with a barb that glistened with toxin, erupted from her abdomen. Her body swelled, bones cracking and reforming, muscle fibers multiplying. In two seconds, she went from a limping, broken woman to something that filled the corridor from wall to wall.

  "MY BABY! WHO TOUCHED MY BABY!"

  She charged through the open door.

  The sounds that followed were not sounds David wanted to catalogue. They were the sounds of a high-tier entity encountering the staff of a restricted zone and discovering that her grief, weaponized and amplified by months or years of searching, exceeded their combined defensive capability. Metal tore. Flesh ruptured. Something that might have been a scream or might have been structural failure echoed from deep inside Car 13.

  David released the cleaner entity. The Bear Spirit consumed it in three efficient bites—a loose end tied, a witness eliminated. Then David straightened his coat, wiped the blood from his nose, and walked through the open door into the slaughterhouse.