Flying Witch 8
Blurb on the back of the book:
Makoto and her family journey to the peaceful region of Shimokita, where a mysterious figure called “Enigumo” can supposedly help Makoto find out which element she can control. The cousins chow down on sea urchin and have fun at the beach, completely unaware that her element might defy all expectations... Join the gang on this mystical—and surprisingly explosive—adventure!