MC is a new tenant in an old apartment building and one day she woke up and she was still in her apartment but it looked newer and she found out it was a year in the past. ML is still a young boy like high school student. And she lived with the boy and kinda raised him by working as part timer in a convenience store. ML's inheritance money from his grandma is being controlled by his aunt as his guardian. One day she went back to her present time and dont know and left the boy in the past. The old man in the building has alzheimers but remembers her name so well even if she was a new tenant because when she was in the past she always greeted him in the morning.