Hina no Mama ja Dame desu ka?  

ヒナのままじゃだめですか？, Why can't we stay as children?

Hina, a fifth grader, had a secret that she could not tell anyone. It is that she started menstruating three months ago. This is a story of a girl's growth, who is puzzled by the changes in her body and mind on the threshold of puberty.(Source: Nico Nico Seiga, translated)