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A few weeks have passed since Haru's mother remarried.
She and Haru's new stepdad are to go away for a honeymoon for one week.
Haru accepts this, knowing that getting time off and having a holiday isn't an easy feat.
However, there is one small thing he is worried about.
That is... his new older stepsister Akane, a university student.
Both Haru and Akane are not particularly assertive or socially extroverted, and even though they may be living together, the two have hardly even spoken.
While their parents are away, they will be left alone together.
And Haru isn't looking forward to it one bit. However, considering it's only one week...
I can just avoid her by playing games in his room or something, Haru thinks... with no intention on improving his relationship with Akane.
On the day that their parents leave... the two wave goodbye, return inside. No conversation whatsoever.
"When dinner's ready, I'll call you..." Haru says.
Akane simply acknowledges and they part.
Gazing aimlessly at the ceiling of his room from his bed, Haru worries about the coming week. The
Thinking about how the atmosphere between them is such a drag... he eventually falls asleep.
The next time he opens his eyes, the room is dark, and something is not quite right...
He feels cumbersome... as if something is on top of him...?
Straining his eyes, he sees that it's Akane.
But again something is not quite right...
Both his, and Akane's lower body are exposed... and their genitals touching one another.
Unconcerned with Haru's bewilderment, Akane sways and swings her hips.
Thus begins, Haru and Akane's 7 days alone together.