Three kids explore a mysterious and enchanted flooded city. The illustrations are cute and charming. If feel like you entered into a mysterious adventure. The story is short, there are three volumes of this doujishi. This doujishi is for all ages. This series is highly recommended to read. 

https://aqua.irodoricomics.com/raincoat_kids_1?search=rain

and Available on Kindle:

https://www.amazon.com/dp/B084DB7DCT