Usato Ken is a regular second-year high school student. On a certain rainy day the two most admired people of the student council, Inukami Suzune and Ryuusen Kazuki, notice that he doesn't have an umbrella. They end up talking as they walk together, but they are suddenly summoned to another world as heroes. It seems as though Ken was dragged into the summoning, but he can't return to Earth. What will he do? Will he mope around in despair or will he take action?