The protagonist messes up with a FX trading and gets into a huge debt. He is send to an underground arena where illegal matches are made to entertain the riches all over the world.
All you have to do is to win. Win, get the cash prize and have your way with the losers!

Battle with a choice of commands! Fight against others and win to survive or your life is over! Train yourself and continue to win!
And you can do whatever you want to the losers, and most of them are female fighters!

[From DLsite English]