Raising kids with Joshikosei is a busy but rewarding everyday life! Kuremoto Kyota is a high school student who loves his 3 year old sister. His parents worked together to do housework and take care of the children. Akiyama Sumi is a lonely girl with beauty and a clear mind. She distanced herself from everyone because of her aura. One day, Kyota, who was attending the park’s acceptance ceremony sister’s kindergarten, surprised to find Sumi taking pictures of her sister like a cameraman. “Iku, how cute…” Turns out she’s a brocon too! Knowing that they take care of each other’s younger siblings, they gradually begin to deepen their relationship. Cooking, picking up sister at kindergarten, weekend dates. Yes, the relationship between the two is exactly like “Mamatomo”. Romcom child rearing has begin!