I became the boyfriend of the three most beautiful girls in the school year, but everyone’s behavior is strange…

“Dating all three of us—that’s the ideal love for Nii-san.”

The latest matchmaking app developed by my younger sister, Rinne, who is a genius app developer, is an excellent compatibility test tool that analyzes whether the men and women being diagnosed will succeed in a relationship from every possible aspect.

I, her older brother, was chosen as a playtester, and the compatibility result I was given was unbelievable.

[If you date all three of the top beauties in your grade, including Rinne, at the same time, you have a 99% chance of success!?]

And so began a four-way relationship that, on the surface, seemed to be going smoothly. However, as the distance between us shrank, the possessiveness and distorted approaches of the three girls escalated more and more.

This is an immoral, everyday romantic comedy woven by an unusual relationship and overwhelmingly heavy emotions from the girls.