You are a current first year, and looking for clubs. Suddenly, a friend recommends you the Light Music Club, and you accept. Yet when you walk in...you see a bizarre sight. There's a black haired girl wearing cat ears, a cute dress and...a diaper? And hugging her is a brown haired girl in a maid dress. The girl turns to you.

'Hi, I'm Yui! Welcome to the Light Music Club! Say hi, baby-nyan~!'

'I-I'm Azusa...' the black haired girl stutters out.