Chapters 3-12 detail the protagonist, Mason, a former member of the Hero Party, as he navigates his new life as a fledgling adventurer. Initially, Mason is unceremoniously expelled from the Hero Party by the Hero, Rondo, who labels him "useless" and a burden, despite Mason's contributions in scouting and weakening monsters using his "Plunder" skill. Heartbroken and feeling betrayed by his supposed friends, Mason retreats to an inn for several days before seeking work at the Adventurer's Guild.
His first solo quest involves gathering monster materials in a forest. Here, Mason discovers his "Plunder" skill can extract abilities from monsters, such as "Minor Body Reinforcement" from a Kobold, which he uses to easily defeat Goblins. He then stumbles upon a group of Elves, including the beautiful Luna, being attacked by a Treant. Mason intervenes, using "Plunder" to steal the Treant's "Auto-Heal" and then defeating it with his enhanced strength. The Elves, particularly Luna, are surprised by his swift victory. Luna introduces herself and expresses gratitude, but her companions, especially one of the male Elves, are wary and quickly usher her away, promising to repay their debt later and heading towards the neighboring country of Landoria.
Mason returns to the Guild and successfully turns in monster materials, including a necklace from a Goblin Magician and a branch from the Treant, earning him a surprisingly large reward of three gold coins. The Guild Master, Gail, informs him that he's being promoted from F-rank to D-rank adventurer and is summoned to the royal palace the next day, a summons he finds perplexing given his recent expulsion.
Upon arriving at the palace, Mason is met by Rondo, who cruelly berates him, calling him useless and telling him to leave. Mason endures this humiliation before being led to the throne room. There, he discovers the person who summoned him is none other than Luna, who reveals herself to be Luna Arcless, the First Princess of the Elves. She offers Mason a position as her knight, explaining that she values his strength and that a prophecy foretold someone would help her. Mason, despite his initial shock and lingering resentment towards Rondo, accepts.
Luna reveals her true mission: to rescue her younger brother, Lutz, who is imprisoned by demons. She explains that Lutz used a "Diamond Lock" spell, a form of self-imprisonment using gems, to protect himself from harm, meaning he is not in immediate danger but needs rescuing soon. Luna plans to operate undercover as an adventurer while searching for Lutz, and she wants Mason to join her. She also warns Mason not to tell Rondo or the Hero Party about their plans, as there's a suspicion of a demon-affiliated individual within Rondo's circle.
Mason and Luna begin their adventuring career together, taking on a "Graveyard Exorcism" quest. During this mission, they encounter a Lich, a powerful monster, and Mason uses "Plunder" to acquire "Raise Dead" and "Drain" skills. Luna uses her "Holy Heal" to exorcise the graveyard, while Mason fights off the summoned skeletons. They defeat the Lich and recover a staff, which turns out to be a lost national treasure of Landoria. This event leads to them both being promoted to D-rank adventurers.
Later, Rondo and his companions are shown struggling against seemingly stronger goblins, with Rondo lamenting Mason's departure and questioning if it's the cause, though he quickly dismisses the idea. Rondo then encounters Luna and Mason at the Adventurer's Guild, mocking them. Luna defends Mason, highlighting their D-rank status. Rondo, arrogant as ever, dismisses them. Luna, fueled by Rondo's arrogance and Mason's own hurt, proposes they prove him wrong by becoming stronger and ultimately defeating the Demon Lord themselves, a goal that Mason reluctantly agrees to. The narrative concludes with a hint that Mason's "Plunder" skill is more significant than he realizes.
