Kinokoinu

Storybook author Hotaru is depressed, unable to focus on work after losing his beloved dog, Hanako. A strange creature shows up in his yard that looks like a mushroom but also a dog. Komako, his childhood friend and editor, is baffled by the situation.

Itsuki is a superfan of Hotaru and falls in love with him at first sight. Hotaru is tricked by Komako to accepting an interview and photoshoot for a dog magazine. Hotaru is struck with an intense realization after taking Kinokoinu on a walk.

Hotaru gets frustrated at Kinokoinu for disrupting his work. Kinokoinu gets upset and runs away after Hotaru compares it to Hanako.

"Hotaru catches Kinokoinu releasing spores in the morning. Komako hosts a Halloween takoyaki party for Kinokoinu. Kinokoinu releases white spores after the party at night, which is a spectacular sight."

Hotaru leaves Kinokoinu at home with Itsuki for a night to attend an author signing event with Komako. Kinokoinu learns hiragana with Itsuki while Hotaru is away.

"Anzu bumps into Hotaru at the bookstore and ends up coming over to visit Kinokoinu. Anzu ""kidnaps"" Kinokoinu so it can meet Plum."

Turns out Plums is Kinokoinu's sibling formed from its spores. Plum lives with Anzu and her mom, Tsubaki. Tsubaki used to tease Hotaru in elementary school and is also a picture book author. Hotaru decides to get a cell phone after years of refusing.

Tsubaki drops Plum off at Hotaru's after her ex-husband calls to meet up. Komako and Kinokoinu go shopping after the takoyaki pan breaks.

Kinokoinu meets Komako's brother Ayumi, who is the creator of "Snail-Senpai." It also meets Hino-san, the neighbor across the street. Both Ayumi and Hino-san are not startled by Kinokoinu's existence.

Kinokoinu meets Hino-kun and his son, Toshi, at the park. Toshi is a huge fan of Kinokoinu and asks for its autograph. Hotaru decides to join Ayumi to visit his family's grave, where Hanako is buried.

Hotaru visits his family's grave with Ayumi and Kinokoinu by the beach. Hotaru remembers that Grandma was the one who found Kinokoinu and brought it to the yard.

Hotaru finds Grandma's diary and reads about her first encounter with Kinokoinu. The diary gets damaged in the rain so not much is revealed. Kinokoinu remembers Grandma asking it to help Hotaru when he feels sad and lonely.