Rudd, who is an adventurer in the remote city of Barona, has no fighting ability and is hated by his fellow adventurers, calling him a "miasma scavenger.". He spends his days exploring the miasma labyrinth using his only skill, "state anomaly nullification," but one day he hears that a new labyrinth has been discovered. An adventurer calls out to Rudd, who is about to head towards her.

Rudd is invited by the adventurer Bayer to accompany him to the New Labyrinth as a porter for his party, the Scarlet Sword. The strategy progresses smoothly, but a powerful enemy, the Minotaur, that should not have appeared appears...!?

At the guild, Vaiell delivered the lie with a pale face. "The Minotaur killed him. Rudd is dead". Fear gripped the room. But then, the doors creaked open. A heavy scent of blood and miasma flooded the hall as a shadow emerged. "Dead? That's news to me, Vaiell". It was Rudd. But his eyes were no longer those of a scavenger-they were the eyes of a predator.

Rudd falls into the trap of the Lizardman and finds herself in a predicament. Observing the enemy in search of a solution, he notices the alien skills hidden in an individual. At that time, I met an elf girl who was about to fall into the hands of an adventurer hunting demon.

Five years ago, the Elf girl Elyssia lost everything in the labyrinth. Her party disbanded, and she was struck by a cruel "Level-Down Curse". As her strength withered away, it was Rudd, the shunned adventurer, who reached out to save her.

Rudd and Elyssia were visiting the Baronamas fishing grounds, which they had heard about from the tavern owner. When they learned that the local specialty, Baronamas dishes, could no longer be served due to monsters, the two decided to go and defeat them at the owner's request.

Having teamed up with Elyssia, Rudd sets out on their first mission: to defeat a pack of gray wolves. There, Rudd witnesses Elyssia's true abilities for the first time. He is struck by the realization that the power of a former S-rank adventurer is no joke.

Having defeated the formidable Baphomet and restored peace to the village, the two prepare to use their newly acquired powers. However, they notice something odd. The source that powers the monsters' skills is not the "magic power" that humans wield, but rather the "magical essence" that permeates this world.

To find a replacement for their broken sword, the two visit Doem, a blacksmith and friend of Rudd's. At the same time, Rondo, Magnus, and Rigurd, who were exploring a labyrinth, find a sword emitting an ominous aura in its deepest part.

To save Rondo from being consumed by the curse, Rudd confronts the demonic sword. However, the sword's power is immense, and he is pushed into a defensive position. Elyssia comes to his aid, but the two are still in dire straits.

Rudd and Elyssia visit the new Abellio Labyrinth in order to defeat the "Miasma Dragon Basilista." As Rudd wields the magic sword he has acquired, he becomes confident in its rigidity, which can withstand even a blow infused with magic essence, and in the hidden power that has been newly discovered. The two were making good progress, but suddenly a tremendous roar echoed through the labyrinth—

With Elyssia's magic power depleted, Rudd takes her place and confronts Basilista alone. Rudd puts up a good fight, but is eventually cornered by the dying Basilista's desperate counterattack.