The main character Kaoru is one of two twins. His sister Kaede died when they were little falling off a cliff, leaving his mother in shock. That's when the MC decided to dress up as Kaede so his mother can continue living her life (she's quite insane nevertheless).
In the current day, Kaoru decided to live on his own while being a student.
He often talks with his childhood friend (who is not gay; he was in love with Kaede for a long time, this is why it is hard for him to see Kaoru dress up & pose as Kaede).
When he meets Reika, Kaoru asks her if she's into girls, but she tells him that she actually isn't (it's probably due to her "traumatic" childhood where her parents didn't give her any love; she met Saotome-san at her high school and felt some kind of connection with her after she stood up to bullies engaging Reika).
Kaoru also gets to meet Saotome-san, who is also a cross dresser (she is a girl dressing up as a boy), what is only discovered later when there is only one female toilet available and she confesses being a girl.
Reika is getting closer to Kaoru because she wants to get closer to Saotome-san again and discovers that Kaoru is a cross dresser, confronting Kaorus childhood friend with her findings. Meanwhile Saotome is still oblivious to the fact that Kaoru is a man although she met Kaorus mother and learned about Kaorus & Kaedes past.