Otouto no Omokage

In the year Showa 10, a strange friendship is born between Akihiko, a boy who dreams of becoming a doctor, and Hisao, a girl with a prosthetic hand, when they meet at a medical exhibition. However, every time Hisao meets Akihiko, Hisao's body deteriorates as parts are replaced by prosthetics...... This retro science fiction drama is full of darkness and beauty, questioning the nature of humanity and independence!

(Source: Kodansha, translated)

Note: Afternoon Shiki-sho award winner for Spring 2024.