木下 卯月

The protagonist, Takumi Mizukami's, imouto who adores her onii-chan. After losing both their parents in a disaster, due to ***** circumstances, they were separated half-way through their upbringing. She lives in Sendai. 

Even after being separated, she never forgets about her onii-chan and constantly brags about how stoic but kind he is. Despite being a natural beauty, she has not had any relationships with the opposite sex due to setting her onii-chan as her standard. Due to this, her friends tease her for having a brother complex.

One day while browsing the Aikotoba app, she stumbles across a user with the alias "Takumi" who she has a "99% compatibility score" with. Using the alias "Yozora", she takes a gamble on destiny and slides into his DMs. Their communications carry on until one day, "Takumi" tells her that he'll be in Sendai for business. Seizing the opportunity, she proposes the two should meet up.

After 7 years of harboring her feelings of adoration for onii-chan, her adoration escalates into a passionate love. As she begins to pursue her onii-chan more and more aggressively, worries surmount.