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 him as the mythical folklore youkai known as a kappa. kouchi finding him rather cute and initially seeing him as a unique pet decides to take care of him along with the help of his family.

this is the simple barebones premise and would seem like a perfect comfy watch while you drink a warm cup of coffee in the afternoon, but this one is more than just another cute comfort film.

summer days with coo is a modern cautionary folktale about humanities cruelness towards what it cannot understand.our fear of what we cannot comprehend, of anything abnormal, whatever challenges our beliefs. the harshness we tend to show to the illogical, resorting to cruelty in an attempt to take control of what is outside our grasp.

this is not only shown through peoples reactions of fear or over-invasiveness towards the "kappa" coo, but is also displayed in the harsh bullying of several kids that is shown and mentioned in certain parts of the film. humans are ugly creatures, and the artsyle and character designs amplify this theme with admittedly ugly or offputting looking faces which is a clear choice to further hammer down how ugly humans can really be.

the soundtrack is also haunting and creepy at times and reminds it's viewer that this is not just your typical feel good summer family movie, it may look and feel like one from a surface level of viewing but there are darker tones to it hidden behind all the bubbliness and the brightness.

"our kind does not lie, only humans tell lies".

as realistic and dark the films core themes are, it does not resort to saying that humans cannot have kindness in their hearts. saying that inspite of the overwhelming abundance of bad people on earth there are a few good ones mixed among the crowd. coo has lived his life being told by his father that humans are an awful species and finds out that this is indeed true but also learns that not every single one is, that there are humans who will see him more than just a circus freak or a myth come to life, ones who look past appearances and see the heart.