“Working Part-Time as an Adventurer in Another World” – Himawari Mart’s Warehouse No. 4

Takana Mika is a thirty-eight-year-old mother of two who works part-time at Himawari Mart, a small supermarket in a town of thirty thousand. Her life is mundane until she is assigned to clean and restock Warehouse No. 4, a converted air-raid shelter built into a cliffside. The store manager warns her about a "black demon" lurking inside, a euphemism that Mika initially assumes refers to cockroaches. Upon entering, however, she discovers that the warehouse connects to a vast, dimly lit dungeon filled with magical creatures. Mika encounters bat-like demons, fireballs, and lizardmen, which she dispatches using insecticide and a heavy rake. Over six months, she becomes desensitized to the dangers, treating the dungeon monsters as pests to be cleaned up while collecting antiques for the store.

Mika’s routine is interrupted when she is diagnosed with early-stage cancer and takes a two-month leave for surgery. During her absence, the dungeon’s nature remains a secret, known only to her. Upon her return, she finds the warehouse has transformed back into the cavernous dungeon, confirming that the space shifts between a normal storage area and a magical realm depending on the user or perhaps the passage of time. While exploring, she encounters three humanoid creatures: Dada, a birdfolk adventurer; Gatt, a kobold swordsman; and Zurah, a lizardman mage. They reveal that they are humans in this world, while Mika is considered an "ogre," a term for powerful, intelligent beings. The trio explains that they have formed a contract with her, allowing them to communicate telepathically, and they beg for her help against a looming threat.

The world Mika has entered is Salichil, a nation where various races coexist. A Sage has prophesied the revival of the Demon King, a catastrophic entity that appears periodically to devastate nations. The immediate precursor to the Demon King’s return is a surge in monster activity. The Adventurer’s Guild, led by a lizardman named Zieg, identifies Mika as the key to stopping this calamity. They reveal that the Ogre boss of the dungeon’s 60th floor is the only being capable of sealing the Demon King away. Dada’s mission was to tame this Ogre, and through the contract, Mika has inadvertently fulfilled this role. The Guild offers Mika a deal: she will register as an adventurer, gain strength by clearing dungeons, and eventually face the Demon King. In return, she will receive wealth, a residence in the capital city of Acid, and a personal Door artifact that allows instant travel between her world and Salichil.

Mika agrees to the proposal, partly due to the financial incentives and partly because the Guild assures her that the Demon King is not necessarily evil but rather a force of nature that must be pacified. She is joined by Takayuki Yamano, the eighty-seven-year-old founder of Himawari Mart, who reveals he is an SS-rank adventurer known as "Tacky the Ogre." Takayuki has been secretly observing Mika’s progress and provides guidance on navigating the dungeon’s complexities. He explains that the antiques Mika collects are actually items dropped by defeated monsters, which reappear in the dungeon over time. Mika’s level is estimated to be around 50, making her significantly stronger than the average adventurer, who typically hovers around level 30.

The story follows Mika as she balances her part-time job with her new duties as a dungeon delver. She learns to distinguish between hostile monsters and civilized races, such as fairies and snakefolk, avoiding unnecessary conflicts. Her first major quest involves clearing a mine infested with Iblieth, a swarm of black demons that drain magic from living beings. Mika demonstrates her combat prowess by physically trampling and striking the swarm with her rake, protecting her companions. The narrative establishes her role as a protector figure, leveraging her mundane household skills and resilience to tackle supernatural threats. As the Demon King’s revival draws nearer, Mika and her party prepare for the ultimate confrontation, navigating the political and magical intricacies of Salichil while maintaining her connection to her family and life in the human world.