One morning, high school student Haruka finds himself and his entire class standing inside a magic circle. A god has summoned them to another world and declares they will become heroes. Each student is allowed to pick a special skill from a vast list, but Haruka, who tried to run from the selection ritual, arrives last. Every desirable ability has already been claimed, and the god dumps all the leftover, seemingly useless skills on him. Far from being discouraged, Haruka sees this as an opportunity to live exactly as he wants: alone, in peace, without depending on anyone.

The world he lands in is a dangerous fantasy realm filled with monsters, dungeons, and a medieval society ruled by nobility and adventurer guilds. Haruka quickly discovers that his collection of cast-off abilities is far more useful than anyone expected. With a combination of basic magic, a bottomless storage bag, and the uniquely named Loner skill, he establishes a comfortable solo routine inside a forest dungeon. He hunts, crafts, and levels up at his own pace, all while keeping his true capabilities hidden from his former classmates.

Haruka is a deadpan, sarcastic teenager who genuinely prefers being by himself. He has no interest in leading anyone or playing the hero, yet he cannot ignore others in genuine trouble. The other major characters are his classmates, who quickly fragment into hostile cliques. There are the delinquents, the athletes, the nerds, the class representatives, and the gyarus. Touka Tsuyuri, the serious and capable class representative, becomes one of the few people Haruka tolerates. A group of otaku students, who picked powerful magic skills based on their knowledge of fantasy games, initially try to protect the class but are driven away by misunderstandings. The gyaru girls, flashy and social, end up in serious danger and seek Haruka's help.

A major narrative arc begins when Haruka reluctantly shelters a group of stranded classmates, only to find himself caught in the escalating infighting between the different factions. He must navigate the cliques’ petty rivalries and conflicting priorities to keep everyone alive. Another key arc follows his arrival at the ducal town of Omui. There, he rescues the duke's daughter, Merielle, from bandits, and she insists he stay as a guest. While he tries to escape back to the forest, Touka and the others inadvertently drag him into town politics and dungeon expeditions. An accidental misuse of a mental domination skill on the gyaru girls creates a darkly comic situation where he robs them of their free will, a moment the story treats with unsettling levity. Throughout these events, Haruka repeatedly lies about his abilities and tries to keep his distance, yet his actions keep pulling the group closer to him, forming an unintended circle of dependents that he must protect. A second season of the anime has been announced.