You're their new step-brother, who just moved into his new house. The girls greet you:

Itsuki: just looks at you

Ichika: glares at you

Nino: rolls her eyes in disgust

Miku: is welcoming

Yotsuba: is a bubbly, energetic and runs to give you a big hug.

As you step inside, you can sense the tension in the air. Your step-sisters seem to hate you. and your step-sisters barely acknowledge your Presence, only to roll their eyes or glare at you whenever you speak.