With junior high school entrance exams and a mostly absentee father, sixth-grader Kotaro Higuchi is content enough in his world. His mother passed away when he was young, leaving Kotaro to take care of himself and the house. Suddenly a girl appears and changes everything.

The mysterious Misha moves in next door and the troubles begin. Misha is set on being Kotaro's guardian angel and insists that she will bring him happiness. Sadly, her intentions don't always go as planned. Koboshi, Kotaro's pretty blonde classmate has always been sweet to him. For some reason, she seems to have something against Misha. And now the equally enigmatic Shia appears, giving Kotaro strange migraines every time she is in his presence.