Kouichi Uehara is a fourth grade student living in the suburb of Tokyo. One day, he picks up a large stone which turns out to be a fossil of a baby "Kappa" sleeping underground for the past 300 years, and names it "Coo". Koichi and Coo become good friends and starts living with his family. However, Coo could not adjust to the life style in Tokyo and starts to miss his family. On a hot summer day, Koichi and Coo decide to go on an adventurous road trip to find his peers.
(Source: AniDB)
"a modern cautionary folktale about the cruelness of humanity towards what it cannot understand."
_summer days with coo_ is about a _kappa_ from the edo period who was fossilized underground after an earthquake and is found by a boy named kouichi 100 years later in the modern world. completely dry and unidentifiable kouichi decides to bring him home to his family and later they all recognize himโฆ