A man grieving his dead dog finds a mushroom growing in his garden that wags its tail. The show knows it's not trying to fix his sadness, it's just letting him sit with it, drawing, watching this impossible thing breathe. The magic here is that nothing happens, and somehow that's exactly what he needed.

Hotaru Yuuyami, a picture book author drowning in grief over his lost dog Hanako, finds an unexpected companion beneath the snow willow in his garden: a small pink mushroom that moves, wags its tail and edges toward him. Bewildered but drawn to this peculiar creature, he welcomes it into his home and his life. What unfolds is a gentle collision between order and chaos. Kinokoinu has no concept of house rules. It draws in places it shouldn't, polishes off all the melon bread and takoyaki, and turns quiet moments into comedic messes. Yet its playful nature is hard to resent, and the days spent with it slowly change Hotaru's expression. Alongside his childhood friend Komako, his editor and Yara of the Mushroom Research Institute, Hotaru shares funny, heartwarming days with a companion that remains a mystery in many ways.