Amasawa Miyako, the middle child of 5 siblings, is the only 'normal' one, the others all being very good-looking and very talented at something. She takes care of them at home with cooking, cleaning, etc. because their parents are very busy at work, but she has to deal with both her own insecurities and people's opinions on how she's not like her brothers and sisters. It also doesn't help that she likes her best friend who's in love with her older sister...
Note: Ch1-2 released by Bad Eggs are Volume 2 chapter 2a and b.
Note 2: The 3rd and 4th chapters are the oneshot called: Sora no Mannaka ~Spring Storm~