Hajime Nagumo, an ordinary high school student, is transported to a fantasy world alongside his classmates as part of a summoning ritual to combat demonkind. Unlike his peers, who receive powerful combat abilities, Hajime is granted the seemingly weak transmutation skill, which allows him to manipulate materials. Ostracized and ridiculed for his lack of strength, Hajime’s life takes a drastic turn during a dungeon expedition when he is betrayed and left for dead by a classmate. Falling into the depths of the abyss, Hajime undergoes a harrowing transformation, both physically and mentally, as he struggles to survive against monstrous creatures.

In the labyrinth, Hajime discovers ancient artifacts and forges powerful weapons, including firearms, using his transmutation skill. His determination to return home drives him to grow stronger, and he forms a bond with Yue, a vampire princess imprisoned in the dungeon. Together, they escape the abyss and embark on a journey to collect the ancient magic artifacts known as Liberators’ relics, which hold the key to returning to Earth. Along the way, they are joined by other companions, including the dragon-girl Shea, the priestess Kaori, and the bunny-eared warrior Tio, each contributing unique abilities and personalities to the group.

The narrative explores themes of survival, resilience, and the moral complexities of power as Hajime evolves from a vulnerable outcast to a formidable force. His relationships with his companions deepen, particularly with Yue, whose shared experiences and mutual trust form the emotional core of the story. The group faces numerous challenges, including battles with powerful foes, political intrigue, and the revelation of the world’s dark secrets tied to the Liberators and the gods who control it.

As Hajime and his allies gather the relics, they uncover the truth about the summoning ritual and the gods’ manipulation of both humans and demons. The series balances action-packed sequences with moments of camaraderie and humor, while delving into the characters’ backstories and motivations. Hajime’s journey is marked by his struggle to retain his humanity amidst the brutality of the world, as well as his unwavering resolve to protect those he cares about and find a way back home.