The story follows an ordinary old man who one day suddenly is reincarnated as a cute cat, and the president of the company he works for picks him up.

Second season of Hyakushou Kizoku.

Grief-stricken over the death of his last family member, his dog Hanako, picture book writer Hotaru Yuuyami suffers from writer's block for nearly two months. Despite his childhood friend and editor Tsubaki Uehara's best efforts, nothing seems to alleviate his pain. But all of this changes one day with the sudden apparition of Kinoko Inu, a mysterious mushroom from his garden that turns into a dog-shaped animal. Much to the great dismay of Tsubaki, Hotaru hastily invites the creature into his abode. Days after Hotaru and Kinoko Inu start living together, the strange mushroom-dog decides to burn the last of Hanako's personal belongings in order to alleviate Hotaru's depression. However, the cohabitation between the overworked writer and his mischievous guest proves more difficult than expected, and Hotaru must let go of his grief if he wants to properly take care of Kinoko Inu.

This is the story of Puniru the slime and Kotarou, a middle school student, until they cease being friends... Kotarou Kawaii is a second-year middle school boy. When he was in elementary school, a slime he created came to life, and for the past seven years, he has been spending time with the slime named Puniru as his "friend." However, there is one problem for Kotarou... Over the seven years, both have grown significantly, and Puniru has transformed into an incredibly beautiful girl! Besides her beautiful appearance, Puniru freely transforms into various cute forms as a slime, causing Kotarou to be both excited and bewildered by her carefree behavior every time. Will Puniru and Kotarou be able to continue spending time together as "friends" despite these challenging days ahead?