10 Days with My Bratty Stepsister [v1.0.0] [Osawari Honpo]
Due to some family circumstances, your parents ask you to let your stepsister, Nanaka, stay with you for ten days.
You two used to be close, and she was always clinging to you. But when you reunite, you find that Nanaka has become a bratty, distant girl…
Frustrated by her attitude yet captivated by her alluring figure, you decide to make a move on her late one night…
Thread Updated: 2026-10-18
Release Date: 2026-10-10
Original Name: なまいき義妹とヒミツの10日間
Aliases: Namaiki Gimi to Himitsu no 10-nichikan / Namaiki Gimaki 10 / Namaiki Imouto 10 days
Censored: Yes (Mosaics)
Version: 1.0.0
OS: Windows
Language: English, Japanese, Korean, Chinese (Simplified)
Voice: Japanese
Store: DLsite
Genre:
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2DCG, Ahegao, Big Tits, Censored, Creampie, Groping, Japanese Game, Male Protagonist, Masturbation, Multiple Endings, Oral Sex, Point & Click, Rape, Romance, Sleep Sex, Stripping, Titfuck, Vaginal sex, Voiced
Installation:
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1. Extract and run.
Developer Notes:
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◆ Story
You live alone, but due to some family circumstances, your parents ask you to let your stepsister, Nanaka, stay with you for ten days.
You two used to be close, and she was always clinging to you. But when you reunite, you find that Nanaka has grown into a cheeky, sharp-tongued girl…
Frustrated by her bratty attitude yet captivated by her alluring figure, you decide to make a move on her late one night…
◆ Heroine
Name: Nanaka (CV: Mioriaino)
Height: 154 cm
Bust: ???
Nanaka became your stepsister after your parents remarried. She’s at that rebellious age and has developed quite a bratty attitude. Back when you lived together, the two of you were very close.
She’s grown more mature than most girls her age and now has a woman’s figure. She often catches guys giving her leering looks, and she’s received numerous confessions of love… but for some reason, she turns them all down. She keeps her sexual interests a secret to anyone around her.
Game System
This is a simulation game where you raise your stepsister’s affection through conversations while touching her while she sleeps.
Repeat the cycle of “Conversation → Touch → Skill Unlock” to deepen your bond with your stepsister over her stay of 10 days.
Home Screen
On the home screen, you can have conversations and unlock skills.
■ Conversation
Talk to your stepsister to raise her affection!
At first she won’t say much, but as her affection goes up, she’ll open up more.
As her affection rises, lewd events will unlock!
■ Skill Unlock
Use skill points earned from touching to unlock lewd skills.
■ Playtime
Approx. 45–60 minutes
Game Features
- 40+ conversation lines
- 5 CG events
- 3 types of sex scenes (sleeping / affectionate / forced)
- Free Mode after clearing
- Full voice acting (CV: Mioriaino)
If you have any bugs or questions, please leave a comment in Ci-en’s comment section.
We also regularly post development updates, so it’d be great if you could follow along!
