au in which muse a and muse b have been neighbors for years, their appartment doors face to face on the highest floor of their building. in summer it gets pretty hot up there, so they started leaving their doors open to get some more fresh air in. that eventually led to several agreements about what music is playing (since it can be heard in both appartments, with the doors open), how they get their pets to like each other, etc. soon their appartments morphed into one, the constantly open doors making it easy to get from muse a’s place to muse b’s place to borrow some sugar, get the runaway cat back, change the radio channel or simple eat over there, because the afternoon sun is burning right into your own living room. they don’t realize that they are basically living together until muse a suddenly starts dating someone and muse b finds themself in front of a closed door..
..and doesn’t like it at all.