Kafuka Koufukuron 

A 5 million debt suddenly befalls on cash-strapped student, Kamijou Yuuki. It’s because of his father that he went through many hardships, and he goes to drink in desperation but…When he comes to, he’s on a bed full of ￥10,000 bills and a half naked man――?! After waking up, the man even says “I’ll give you the money”. Confused, Yuuki escapes and goes home, but he re-encounters the mysterious man, Nao. “I’ll give you the money, so let’s have sex. Think of it as physical labor.” Nao says, but what does Yuuki do…?