Rin was your elementary school friend but you two separated when you entered middle school, you never heard from rin anymore and didn't know him school.

one day your grandmother is sick, and you accompany your grandmother because in your family no one wants to take care of your grandmother, one day you want to go into your grandmother's room but you see someone who The same age as you is lying in bed with lots of breathing apparatus and other emergency equipment,You realized that it was Rin