A class summoning in another world takes an unexpected turn when one student refuses to participate. Yuji Fujii, caught up in the summoning of his entire class, rejects being transported alongside his peers and instead finds himself reincarnated into the fantasy world as a newborn. He awakens with a changed appearance, now looking like a cute girl, and renames himself Tooi. His new life comes with powerful gifts including the unique Reincarnated Hero job and cheat skills such as the ability to freely view and change his status, detailed appraisal, and an item box. Rather than embracing the role of a savior, Tooi decides to hide his true power and live a peaceful, free second life without the burdens of heroism.

The story follows Tooi as he navigates this world while keeping his identity concealed. His first major decision is to purchase an elderly female slave named Annelise who has been left unsold, intending only to provide her comfort in her final days. However, Annelise reveals her true form as a cursed, breathtakingly beautiful young woman, becoming his first companion and mentor in dungeon exploration. Together, they venture into dungeons where Tooi gradually grows stronger, eventually reaching the pinnacle of human strength through her guidance.

The setting is a standard fantasy world featuring dungeons, adventurer guilds, nobility, and various races. Tooi operates in the shadows of a larger hero narrative, as his former classmates who were transported likely now bear the official hero roles. The tension comes from Tooi balancing his desire for anonymity with his growing power and the relationships he forms, including acquiring other unconventional companions such as a goblin girl who evolves into a beautiful form.

Notable narrative arcs include the Reincarnation Arc where Tooi establishes his new identity and purchases Annelise, the Ennoblement Arc where he gains the title of honorary baron after dealing with bandits and dungeon threats, and the Royal Capital Arc where he faces political intrigue and confrontations with the official heroes. Throughout these arcs, Tooi collects unique party members, unlocks advanced jobs like Assassin, and gradually builds a comfortable life including acquiring a house and capable servants, all while protecting the secret of his Reincarnated Hero status from the world.