Rascal Does Not Dream of a Dreaming Girl (2019) on Netflix

Plot summary

Sakuta Azusagawa, a second-year high school student in Fujisawa, has spent six months with Mai Sakurajima, his girlfriend and senior. Their days together are interrupted by Shoko Makinohara, the first girl he loved, who reappears in his life. While taking his younger sister Kaede to the hospital, Sakuta meets two Shokos: one in middle school, and an adult who once helped him in the past. The younger Shoko has a heart disease that requires a transplant. Both Sakuta and Mai worry about her. The adult Shoko leads Sakuta around, and a rift opens between him and Mai. His scar throbs.