Our protagonist, Ihara Souichirou, married through an arranged marriage to save face.
His wife was married before and had a daughter, Haruka, so the protagonist was initially worried about how his stepdaughter would interact with him.
He didn't think that his teenage daughter would easily accept the presence of a stepfather.
Will she avoid him and stay in her room?
Will she hang out in the entertainment district instead of going home?

However, his fears didn't come true.
In fact, the daughter even showed a fondness for the protagonist.
No, it goes beyond being fond.
She is physically affectionate in a way that isn't typically seen between fathers and daughters.
In an ordinary family, would a daughter rest her head on her father's thigh?
The protagonist couldn't help but feel confused by his daughter's attitude.
His wife's first marriage apparently ended quickly, so his daughter had barely known the love of her father.
Perhaps this is why she sought affection from her stepfather.

But that idea quickly crumbles.
His daughter wasn't looking for love from a father.

Under some circumstances, he realizes that in the back of her mind, she is imagining a relationship with the protagonist.

As a parent, he can't help but feel confused.
But as a man, his male desires are intensely stimulated.
His heart begins to beat faster, anticipating a forbidden relationship with his daughter...