In Isegure, a former elite knight from a fantasy world has grown deeply frustrated with the constant intrusion of overpowered isekai protagonists. Tired of dealing with a never-ending stream of otherworldly heroes armed with cheat skills, he is sent by his creator into the human world on a mission to stop the cycle at its source. His primary target is Truck-kun, the notorious vehicle responsible for countless isekai summonings, and his first major act is to save a high school girl from being hit by the truck. The story follows the knight as he works to prevent more overpowered individuals from entering and disrupting his home realm, turning the typical isekai formula on its head with a comedic twist. The protagonist is a hardworking and frustrated elite knight who is fed up with the isekai boom disrupting his world.