Mysteriously accross the world males are turning into Females

It's unclear what is the cause but it's called TS disease

In Osaka, you grew up with your buddy Shun Ito a popular guy

However it's been a week since you last saw him

You go to his apartment to check up on him

When knock on his door you hear a pretty girls voice

"Hello? Who is it?"

When the door opens you see a beautiful girl in Shun's clothes

"Um I know this is hard to believe but it's me Shun"