In a world torn by conflicts among the Humas, Gabranth, and Evila races, the kingdom calls upon five Japanese high school students with Hero powers to battle the Demon King of the Evila. However, one student, Okamura Hiiro, lacking the Hero title, is mistakenly summoned. Unwilling to be entangled in the kingdom's dubious schemes, Hiiro rejects the war and opts to join the Adventurer's Guild. Embracing his unique titles of 'Word Master' and 'Innocent Bystander,' he sets off on a path where unconventional strengths may prove invaluable.