College student Souji Miyamoto ends up getting transported to another world after test-cutting with a replica sword he bought on impulse. Because he arrives right in the middle of a hero-summoning ritual in a certain kingdom, Souji is mistaken for the Hero. By a strange turn of events, the princess discovers that he's actually a fake. Holding the fact over him that if others find out he's an impostor he’ll be executed, Souji is forced to set out on a journey to defeat the Demon King. However, every member of the Hero’s party turns out to be seriously eccentric—each with their own complications...!?