Studious and intelligent Nagisa Ootsuki is expected to enroll in an elite high school. However, her ideal plan was shattered when she failed to attend the entrance exam after helping a girl who collapsed by the road. Now attending a regular high school, Nagisa has changed her appearance to get a fresh start. But to her surprise, the girl she helped, Mashiro Komiyama, is her classmate! Soon, Mashiro collapses again during class, leaving Nagisa to take her to the infirmary. Mashiro reveals that her body has always been weak, which is why she hates being stuck in infirmaries. Nagisa, feeling stuck at this school, empathizes with Mashiro. She promises to take Mashiro to the infirmary from now on to help her find meaning in her predicament. With every infirmary visit, the girls begin to warm up to each other. [Written by MAL Rewrite]