Sumino is a girl who has always been unnoticeable and has no presence because she is plain and shy. She decides she wants to change and make a least 3 friends in high school. But on the way to school she sees a cat crossing the street that is about to be hit by a car. She stands in front of the cat and tries to be noticeable before being hit. She still gets hit because the driver 'only saw that cat'. She has to go to the hospital for an extended time and misses the first days of high school. When she recovers and starts school again, all the cliques and social groups have already been formed, leaving Sumino in the same position she had in middle school. She is ignored as she always was and even the teacher doesn't recognize her. But then she meets Hinata, a popular boy who is 'like the sun', who really likes her and has always acknowledged her presence. She decides to try to become someone who can stand by the sun.

Throughout the book she confides in her sunflower decorated blog. There she has two followers, Black Rabbit and MegaPIG, who write back supportive messages, where she is known as Himawari.