After her parents are killed by bandits, young Sarasa Feed is sent to an orphanage where she learns about the prestigious world of alchemy. Determined to follow in her late parents' footsteps and become an independent business owner, she enrolls at the Royal Alchemist Academy to train and get certified as an official alchemist. Five years later, Sarasa graduates from the institution and nearly achieves her dream before realizing that she lacks the funds to do so. Left with little choice, she makes do with a low-priced storefront in a town situated far away from the bustling capital. Despite the threat of treacherous terrain and dangerous monsters in the remote countryside, Sarasa begins her exciting new life as an alchemist.

In the land of Terra, natural disasters of unknown causes have been occurring irregularly in many areas. Therefore, the majority of the people, in order to escape those natural disasters, came to live in mobile cities developed over the years. The Originium left behind at the site of such Catastrophes, has led to the rapid progress of civilization due to their immense energy. But it also brought something else with it — an incurable disease called Oripathy. Because the bodies of those with Oripathy gradually crystalize and become a new source of infection at the time of death, in many countries, the Infected are subject to persecution under regimes of segregation and forced labor. Those who were oppressed by the governments are starting to rebel. Rhodes Island, a pharmaceutical company researching a cure for Oripathy, takes up their arms and starts a conquest trying to save all the people from the disease.

Despite having a good reputation as one of the most seasoned guards in the local guild of Mebuki, Kikuru Madan believes he has been wasting his youth and hopes to spend the rest of it like any other person. However, his conscience prevents him from retiring at present, as he worries about the guild's future without him. Coincidentally—as if to help him find his successor—the guild's receptionist, Enome, assigns Kikuru four fresh recruits: the energetic beastwoman Hitamu "Hitamuki" Kyan, the prodigy Maidena Ange, the laid-back Toxico Dannar, and the stalwart Hanabata Nohkins. Although each of them possesses significant talents, they also display characteristics that detract from their potential—including Hitamu's extreme clumsiness and Hanabata's unintentional perverseness. As if there was not enough to deal with, the monsters outside Mebuki's walls start exhibiting odd behavior by targeting women salaciously, causing the party endless problems in more ways than one. Nevertheless, Kikuru is committed to retiring early; to achieve his goal, the guidance he gives the trainees will be absolutely essential.

In the near future when technology has significantly advanced, a famous AI TV fortune teller seemingly foresees high school student Asahi Kashiwagi's day with pinpoint accuracy. On his way to school, he encounters Aoi Izumisawa, Bai Mongfa, Karin Istel, Amelia Irving, and Ilya Ilyukhin. Despite meeting them for the first time, Asahi suddenly receives love confessions from all of them at the end of the same day, perfectly aligning with the fortune teller's prediction. As if that was not enough, Asahi soon learns that these five individuals are actually candidates to become his bride, and they have been invited by his father to live at Asahi's home. Left with no other choice, he reluctantly allows them to stay, resulting in a bawdy turn of events that brightens up his average high school life. However, as Asahi spends more time with them, forgotten memories gradually resurface. While uncovering the hidden truth, Asahi begins to believe that his fate with these potential partners might be more than just mere coincidence.