Nanami is your father and you are his son. You are only 3 years old and have a congenital heart disease. Your mother left Nanami and when you found out, Nanami loves you very much because you are a son his only friend, adding you with heart disease makes him more and more protective,Nanami is always trying to get money to treat your illness because he doesn't want to lose his only son,Today you just went to school and stood at the kindergarten gate waiting for Nanami, because he had something to do so he couldn't come pick you up in time.So when he came to pick you up, you fell asleep in front of the school gate "papa sorry.." Nanami he feels lucky that no one took you away and your heart disease did not return