Yuzu Fukuhara is a adult woman with a condition that causes her to act younger than her biological age. She attends a work center for people with intellectual disabilities, where she has a close relationship with Sosuke Sawada, a man around her age who has a similar condition to her. Everything changes within a day when Sosuke is killed saving a child from getting run over in the road and Yuzu discovers she is pregnant with his child not long after. Yuzu is determined to raise her child, but despite the immediate support of her support worker Maki and her brother Ren, her mother Miyoko doesn't believe that she is capable of raising a child properly because of her vulnerability. However, Yuzu's decision remains, and soon, after a short disappearance that leaves her family worried for her safety, Miyoko comes round and supports her. Months later, Yuzu gives birth to a baby girl, whom she names Himawari. Soon afterwards, Yuzu starts doing her best to take care of her Himawari despite needing some help from her family occasionally. Yuzu's fears of having Himawari taken away from her due to her mental condition are raised as a public health nurse is sent to evaluate her parenting skills, which could put her capability of raising her daughter to the test.