"I must be crazy, falling in love with my childhood friend's father----"

Nao is a girl living in a small country town in the mountains. She has been spending her remaining time as a student there, while taking care of her childhood friend, Hiroki, who is a little unreliable and has been with her since they were young. She is spending her time at school peacefully, as she nears graduation.

Hiroki's father, Masaki, gently watches over them both. His wife died of illness at about the same time Hiroki was born, and so he has been raising Hiroki all by himself. Nao wants to help him with that, so she has been going to Hiroki and Masaki's house every morning to help out, and has grown to love him as if he were her real father.

On the day of his high school graduation, Hiroki finally decides to confess his one-sided love to Nao, whom he has crushed on for many years. However, after the graduation ceremony, Hiroki is stopped by their other childhood friend, Sayuki. She had decided to move to Tokyo to go to college alone, and asks Hiroki to come to her home to ask him to listen to her problems.

--Hiroki was supposed to tell Nao about his feelings for her that night, but what he said was...

"I'm moving to Tokyo with Sayuki."

Sayuki pleaded with Hiroki to go to Tokyo with her, and Hiroki could not refuse, and so chose her instead of Nao.

Later, Nao saw them off, being as cheerful as usual, as they boarded the train to Tokyo.
However, she was in tears on the way home, confused about how her heart got broken and her feelings rejected, before she had even realized she had any.

It was Masaki, Hiroki's father, who found Nao and reached out to her.

Several years have passed since then.

After Hiroki left, she spent a lot of time with Masaki, and they lived their lives together almost as if they were a newlywed couple.

After some time, she has learned to love Masaki as a man, who used to be like a father to her.

However, Masaki is still in love with his deceased wife. So, Nao is stuck with feelings that will never come true, that she has to cope with all by herself. One day, however, their relationship rapidly grows closer.

"I know your wife will always be your one and only"

"But..."

"I want to be by your side."

Masaki gently kisses Nao, whom he has cherished like a daughter, and reaches out his hand to her soft body, which has not been explored yet...