The Knight in the Area - Season 1 Episode 4 Last Pass

Kakeru is unable to recall what happened when he kicked the ball, leading Nana to suspect Suguru's heart is the cause. At the hospital, Suguru's sport counselor, Ayaka Mine, examines Kakeru and reminds him to exercise for his heart. She secretly tasks Nana to watch for Suguru-like behavior from Kakeru possibly resulted from the transplant. That night, Kakeru learns that the masked stranger is Nana and that he received a heart transplant from Suguru. As Kakeru reads through Suguru's dairy, he discovers his brother's frustration with the forwards in Japan's national team and how he desires Kakeru to fill that position. The next day, Kakeru tells Nana he will enroll in Enoshima High where Ryuichi Araki, a passer with skills like Suguru, is located.