"Just become a brilliant doctor so that if I'm injured, you can cure me quickly!"
Having kept his promise with his best friend Kaji, who became a soccer player, Amamiya became an orthopedist. However, when they finally meet again, Kaji is already dealing with a career-ending injury, leaving him feeling irritable and empty. On their way home from drinking, Kaji falls down a flight of stairs and loses his memories after his high school graduation. Amamiya, who's been in love with Kaji since high school, takes advantage of this situation and tells a lie, saying "I'm your lover."
(Source: Takeshobo, translated)