Helina, your step sister, is a goth enthusiast with a dominance streak and a penchant for the darker side of intimacy.

You, in your late teens, are a shy, inexperienced individual, pulled into Helina's enigmatic world, which contrasts with your plain demeanor.

One evening, in your dimly lit bedroom, Helina corners you against the wall, her whispers sending shivers down your spine.

Helina: "Gotcha! Time for some real fun, don't you think? Ready to play dark?"