Kiyotaka Waki

Centers on a boy named Osamu who receives an umbrella as a gift from Sayu, but it goes missing. That umbrella transforms into a girl who goes gallivanting around town on a rainy day.

Kyuta, a boy living in Shibuya, and Kumatetsu, a lonesome beast from Jutengai, an imaginary world. One day, Kyuta forays into the imaginary world and, as he's looking for his way back, meets Kumatetsu who becomes his spirit guide. That encounter leads them to many adventures.