Aikatsu! - Defying Gravity (Doujinshi)

The male protagonist Utsumi Shinichi is a well known established 31-year old author but has lost his inspiration and is currently living as a shut-in at his grandmother's house in the countryside all alone without barely taking care of himself. Then one day a 10-year-old girl named Haruka stops by and asks Shinichi for permission to take care of a stray cat in his garden. This young girl causes an unexpected reaction in him and he agrees. Shinichi learns that Haruka is an aloof and introverted girl whose parents are barely home: her father travels a lot and her mother is sick in the hospital. After meeting Haruka, Shinichi's editor Oogaki convinces him to use her as inspiration for a new romance novel. Shinichi isn't interested in Haruka in a romantic way, but he pities her because she reminds him of his tragic child self and his lonely childhood. Eventually, they develop an awkward friendship, and somehow they can't leave each other alone. What is in store for them? Why does the laidback Shinichi react this way to this young girl?

A promise of love that Sensei remembers. However, his young student (and also his first and childhood love) has completely forgotten… And he'll make her remember by any means necessary.