Himawari! tells the story of Himawari and her journey to become a Kunoichi, along with her 'vow' to protect her master. Himawari Hinata has recently transferred to Shinobi Gakuen to train and become the best Kunoichi she can be. She has wanted to be a ninja ever since one saved her when she was little. On her first day, she meets Hayato Madenokoji (a new transfer teacher) who saves her life. Hayato does not possess any ninja skills or traits; he is teaching the ninjas about normal society to pay off his debt. However, Himawari notices that Hayato bears the same mark on his neck as the ninja who saved her when she was young.