"Level 1 dakedo Unique Skill de Saikyou desu - Episode 3" begins with Ryota reflecting on his former life as an employee of a black company and his reincarnation into a world where everything is obtained from monsters in dungeons. Although he is only Level 1, Ryota possesses a unique ability that sets all his drop rates to S-rank.

In this episode, Ryota and his companion Emily face off against a terrifying monster. Ryota's unique ability allows him to obtain a weapon from a Stray, a monster that normally shouldn't drop anything, which shouldn't even exist in this world. Despite Ryota's skills being at a low level, they continuously improve thanks to the seeds he finds in the dungeons.

The duo's adventure takes a turn when they encounter Cockroslimes, monsters that drop pumpkins. Emily, who harbors a strong hatred for these cockroach-like monsters, goes berserk and tries to annihilate them. Meanwhile, Ryota discovers that his bullets are effective against the creatures.

During their journey, Ryota and Emily meet Erza, who invites Ryota to eat. Ryota becomes so excited by his new idea that he immediately wants to test it out. He realizes that if he kills a monster outside his designated floor, he is considered a Stray and can obtain unique items like a Freeze Orb.

The episode ends with a tense situation where a swarm of bothersome monster drops falls into the dungeon, threatening to spawn a monster called Femini. The Femini is a dangerous creature that possesses humans and uses them as a nursery to reproduce. Ryota and Emily manage to save the day by utilizing Ryota's Freeze Orbs and Emily's newfound strength, which has significantly increased from battling the advanced monsters.

The episode concludes with Ryota and Emily acknowledging that their partnership is mutually beneficial, and they promise to continue their adventures together.