Twenty-five-year-old Yusuke Yahagi, a man who never felt he had any control over his own life, dies after being hit by a truck. He finds himself in a celestial waiting room where he is informed he will be reincarnated not as a hero or a great mage, but as a dagashi-ya, a seller of cheap and nostalgic Japanese penny candy. He is sent to a fantasy world where his only ability is to magically open a small shop stand. His humble snacks, from Curry Rice Crackers to 10 Rim Gum, possess unexpected properties, such as restoring mana or providing temporary stat boosts to those who eat them. This new world has no concept of dagashi, so Yusuke must introduce them himself, starting from nothing with no money or home.

The story is set in the fantasy town of Luganda, a hub for adventurers who delve into a local dungeon. Yusuke sets up his modest stall, hoping to attract customers. He quickly gains the attention of two young, lively adventurers: the pink-haired Meryl and her friend Mira. They are among the first to realize that his cheap treats offer real combat benefits. Yusuke also catches the interest of a mysterious figure wearing a silver mask and a cloak, who speaks with an effeminate voice and is particularly fond of chocolate. This figure, who other adventurers fear as a shinigami, becomes a regular. After Yusuke casually compliments the beauty of a wanted poster for the Great Witch Michelle, the masked figure grows intensely attached to him, eventually revealing herself to be Michelle in disguise. She is a powerful and possessive, yet sweet, witch who begins working at his shop and becomes his girlfriend.

The main characters include Yusuke Yahagi, a laid-back and pragmatic isekai protagonist who is more interested in running a successful shop and enjoying a slow life than in grand adventures. Michelle is his love interest, a beautiful and powerful Great Witch with a notable yandere streak, who is fiercely protective of Yusuke and initially hides her identity. Meryl and Mira are a comedic duo and Yusuke’s first loyal customers; Meryl is energetic and suffers from hilariously bad luck, while Mira is more level-headed. As Yusuke sells more, his shop magically expands and he gains new products to offer, from stat-boosting snacks to more complex items like poseable Gundam model kits powered by mana.

Notable narrative arcs begin with the initial struggle to establish the dagashi-ya and earn a living in Luganda. A major early arc involves Michelle’s past as a wanted fugitive. As Yusuke unwittingly becomes entangled with her, the main conflict of the first volume is resolved largely by other characters, clearing her name and allowing them to date openly. The series then transitions into a slow-life focus. A subsequent arc sees a vengeful queen plotting against the couple from the shadows, leading to a redemption that is resolved using magical snacks and an angelic intervention. Later, Yusuke discovers that he possesses his own magic and begins mapping the local dungeon to sell his maps to adventurers.

By the fourth volume, Yusuke’s circumstances have changed dramatically. Having become a war hero, he is granted the title of earl and a plot of land in the Royal Capital. The prime location is situated between two schools, making it an ideal spot for his dagashi-ya. Now using a teleporter to travel between Luganda and the capital, Yusuke juggles his dual roles as a feudal lord and a humble shopkeeper, keeping his noble status a secret while his girlfriend Michelle resumes work as a professor. He seeks a quiet life selling snacks to children, but a new, young enemy begins to scheme against him from the shadows, souring his peaceful existence.