Haruka gets cursed with the worst skill in the summoning and somehow becomes the most interesting person in the room. The show knows exactly what it is doing with a loner who stops giving a shit about party dynamics and just gets stronger alone. That's the entire premise, and it never stops being fun to watch him prove everyone wrong.
Haruka's been coasting through high school as a friendless outcast when a divine summons yanks him and his entire class into a fantasy world. A deity offers to grant them magical abilities from a skill list, but by the time Haruka gets his turn, every decent power's already claimed. In a fit of petty rage, the God dumps all the leftover trash abilities onto him instead, making him the laughingstock of his newly transported peers. But Haruka's worst asset becomes his unexpected salvation: the "Loner" skill turns his isolation into genuine strength. While other students rely on teamwork and borrowed power, Haruka discovers his solitary nature lets him access abilities they never could. What looked like the cruelest punishment becomes his greatest edge as he carves out his own path through a dangerous new world. His classmates wanted to be heroes. Haruka just wanted to be left alone. Now he's the one nobody can stop.