At the end of the last summer getaway of senior high school, Youta Narukami spends his days getting ready for the college entrance examinations, when a young girl named Hina all of a sudden appears, announcing herself as the "god of omniscience." Youta is confused and also does not think Hina when she informs him "The world will finish in thirty day." After experiencing Hina's God-like anticipating capacity, Youta begins to believe her powers are genuine. Hina, who is innocent and also childish despite her superordinary powers, decides for one reason or another to remain at Youta's home. Hence starts the begin of their dynamic summer season prior to completion of the globe.