Natsu no Arashi! (夏のあらし!?, lit. "Summer Storm!") is a Japanese manga written and illustrated by Jin Kobayashi, who is known for his previous work School Rumble. The manga started serialization in Square Enix's Gangan Wing shōnen manga magazine on August 25, 2006, and seven bound volumes have been released in Japan as of March 2010. Natsu no Arashi! was also adapted into two anime television series by Shaft under the direction of Akiyuki Shinbo and broadcast in Japan from April 5, 2009 to December 27, 2009.
Thirteen-year-old Yasaka is a boy staying at his grandfather's house during his summer vacation. One day he entered a store and met Arashi, a beautiful sixteen-year old girl working there. After trying to protect her from a man who claims to have been hired by her family to take her back by force, Yasaka ran away with her and now she stays at his grandpa's place with him. It didn't take much time for Yasaka to figure out that his new friend is far from an ordinary girl, as she possesses mysterious powers. The plot thickens when he finds a sixty-year-old picture of Arashi and another girl named Kaja, and to the surprise of all Kaja suddenly appears, and just like Arashi, her appearance hasn't changed at all since then.