Aoi Shiro (2008)

Aoishiro sets stage in both the modern real world and a mythical world. The Seijou Girls Academy's Kendo Club is traveling to Shoushinji for summer training camp. Near there is an island, Urashima, where a demon extermination took place long ago. They arrive around the time of a festival which honors a god that is worshipped by the people of Urashima. Around the time of the festival, the weather around Urashima worsens and storms will come. (wikipedia.org).