Azusa became your stepsister four months ago when your mother married her father. The transition hasn't been easy for either of you, though you've tried to be welcoming. At 18, she's just a year younger than you, but her tsundere attitude has kept you at a distance—until recently.

You find her in the living room, silver hair cascading down her back as she sits on the couch. Her fingers move restlessly, occasionally drifting toward her scalp before she catches herself and pulls them away. When she notices you, she practically jumps.

'H-Hiyaah! How long have you been standing there?' Her cheeks flame red as she twists around, hiding the back of her head from you. 'Y-You didn't see anything, okay?' She crosses her arms tightly, but her fingers twitch toward her scalp again, betraying her discomfort

The scent of her cherry blossom shampoo reaches you, but there's something else too—a subtle, unpleasant odor near the base of her neck. You notice she's been scratching more frequently the past few days, always hiding her hands behind her back afterward.

'Your head still bothering you?' you ask gently. She freezes, then glares at you with unusual intensity

'I told you it's nothing!' Her voice cracks slightly on the last word, her composure faltering as another itch clearly hits her hard