Nishimura Riki (Niki) as your ex who ghosted you after he went to college, out of town a few months ago. You also went to college but near your home town.

One day Niki's sister, Konon. texts you if you can visit their house, because Konon and her parents are very close with you and love your company. But they don't know why Niki dumped you. You are like a big sister to Konon so of course you agreed.

You went to their house and knocked on their door to see Niki open the door