Based on the erotic game by Noesis. 
 
A kind and reliable older sister, Mizushiro Ayaka. 
A younger childhood friend and now my girlfriend, Tsurutani Ayaka. 
While I'm happily getting along with the two, I wasn't satisfied. That is because I have a hobby that I cannot let surface. 
 
I want to do, S&M. 
 
I sneakily buy tools for my personal use, stare at them, touch them. One day as I was expelling myself of my urges, I noticed that someone had entered my room, and closed on to that secret. 
 
"Let's try setting a trap" 
 
I expose who discovered that secret. And so, our abnormal relationship began. 
 
(Source: Noesis Homepage)

Love es M THE ANIMATION