This Sunday, do you want to go to that store we talked about earlier?Sunday?Ah, sorry, I can't. I promised my younger sister we'd go shopping.What's with that look...She's the enemy.Just because she's your sister, I can't be unprepared. I already warned her about this before, but she shouldn't be sleeping together with you.What are you competing over...Ah, sometimes she sleeps with me.She's in for it next time I see her.