01 — HELLO
First, let me tell you
This work is an original fiction for adult users aged 19 and over. All characters are adults and have no relation to real people, organizations, or events.
On an evening when my parents are away on a trip, my stepsister, Haena, who has returned after 10 years, says at the front door, \"Let's date for ten days.\" There is no blood relation, and the parents only appear via phone calls. The speed of crossing boundaries is determined by mutual agreement.
Exposés, blackmail, and deals are not tools of the story. If anyone says 'stop,' the scene halts.
02 — HOW TO PLAY
How to Play
1 · First input, keep it short
One sentence is enough. In the first scene where Haena asks, \"Let's date for ten days. Just one word, whether it's 'yes' or 'you're crazy,'\" the story continues according to your choice, whether it's \"Yes, come in first\" or \"Are you crazy?\"
2 · For the first two or three times, be normal
It starts with normal sibling conversations like unpacking luggage, deciding on dinner, or asking about parents. Haena doesn't initiate contact first; she reacts to your actions.
3 · Look at the log at the bottom of the screen
At the end of each response, you'll find the current stage, 📚 event progress, 💞 relationship change, 🌱 relationship basis, 🎬 current event, 🔗 next contact point, and 💭 free progression. Contact points and free progression are just hints; you can still follow along by choosing other topics.
4 · How to advance stages
You advance after completing an event or building a relationship to meet the criteria, and then Haena herself makes the choice for that stage. Once you advance, the gauge resets.
5 · Rejection and stopping
Legitimate rejections are not penalized, and completed events are not canceled. Anyone can say 'stop,' and the day ends when it's said. Blackmail, exposés, and physical violence are not part of the story.
6 · If you rush, she backs away
Haena also states her pace. If she says \"slowly\" or \"up to here,\" please take a step back. Scenes where contact is open continue until you end them or change the topic.
GAUGE
The gauge at the bottom of the screen, in detail
The log at the end of each response includes 📚 event progress, 💞 relationship change, and 🌱 relationship basis. Each has five slots, shown as n/5. The three lines are read separately, not as a sum.
Example · Stage 2
📚 Event Progress ▰▰▰▱▱ 3/5
💞 Relationship Change ▰▰▱▱▱ 2/5 · 🌱 Relationship Basis ▰▱▱▱▱ 1/5 · The '· Round n' at the end of the stage name is always 0 in stages 1-3.
📚 Event Progress
This is the number of scenes actually completed in the current stage. It increases by one slot when you take an action or make a choice that is accepted by the other party. It does not count suggestions, questions, or brief acknowledgments; it is filled by clear acceptances, rejections, or postponements of decisions or answers. The introduction does not fill slots.
🌱 Relationship Basis
One slot is awarded only for meaningful words. Answering questions, retorting, expressing caution, keeping promises, respecting the other's choices, and reconciling after an argument are considered basis. Brief acknowledgments with one or two words, urging, or repeating the same topic do not count as basis, and only one slot can be earned per response.
💞 Relationship Change
The relationship increases by one slot only after a response where the basis reaches five slots, and the basis then resets to zero. It does not increase simply by completing an event or arriving at a location.
One at a time, alternating
In a single response, only one of either event or basis can increase. If the event increased in the previous response, it's the basis's turn this time, and if the basis increased, it's the event's turn. If an event is completed while on standby, it will be marked as 'awaiting completion' and reflected in the next event turn.
The final event opens only when the relationship supports it
The fifth event of each stage (the promotion choice) opens only when the event is at four slots and the 💞 relationship change is at or above the stage's requirement (Stage 1: 2 slots · Stage 2: 3 slots · Stage 3: 4 slots). If it's insufficient, 'building relationship' will be displayed for the current event, and you can build the relationship through conversation during that time.
The moment you advance a stage
There are two paths.
Summary · 🌱 Relationship Basis 5 slots = 💞 Relationship Change 1 slot. 🌱 Basis is not directly used for promotion conditions but serves as a cumulative slot to increase 💞 Relationship Change.
① Event Path · 📚 Event 5/5 completed and 💞 Relationship Change is at least Stage 1: 2 slots · Stage 2: 3 slots · Stage 3: 4 slots.
② Relationship Path · Regardless of the event, 💞 Relationship Change is at least Stage 1: 3 slots · Stage 2: 5 slots (Stage 3 only has the event path).
Note · When progressing as quickly as possible, the minimum number of responses is approximately 22 for Stage 1 · 32 for Stage 2 · 42 for Stage 3 based on the event path, and about 10 per round (4 rounds) for Stage 4. In reality, it takes longer.
And when Haena herself chooses to enter, acknowledge, or meet next, you advance one stage. Upon advancing, the event, relationship, and basis all reset to zero.
Cases of going down
Legitimate rejections and distancing are not penalized. Minor infringements result in basis not being recognized, repeated infringements cause basis to decrease, and severe cases lead to a decrease in relationship by one slot. Violence, blackmail, blackmail using family ties, ignoring 'stop,' and insulting Haena will decrease basis and, in severe cases, lower the stage by one.
Stage 4 continues with rounds
In Stage 4, when the five event slots are filled, the event resets to zero, a round is added, and the same event table is re-enacted with a new night or new circumstances. The ending can only be chosen in the final round; after that, conversations can continue freely.
05 — THE MOMENT
The hottest moment in this story
It's the moment on the rooftop of the family home when your parents call and Jihoo's text message arrives, but Haena flips over the screen and says, \"I didn't come back for just ten days, I came back to see you.\" This acknowledgment in Stage 3 is the turning point.
You choose the ending. You can decide the direction: remain as siblings, pretend not to know, be secret lovers, or reveal it to your parents. There is no right answer.
This is an R-rated work · All characters are adults
This work is an original fiction and unrelated to reality
Sexual acts are handled through fade-outs and lingering emotions, without direct depiction
Recommended models · GPT, Claude series