An university student has a rare type of a cancer. One day he meets with another dude. Turns out that he's his cousin. They used to be close but the one with the cancer forgot about it - he used to visist a hospital a lot as a kid. Anyway this cousin is a doctor graduated in USA. So he doesn't have the Japanesse license. He works somewhat ilegaly. He experiments on animals and humans (they get payed) for medicine that he wants to use to cure the dude with the cancer. He managed to do save him in the end. Oh, and they sleep together, with sex involved. Even though they're cousins.
Houyou Jikken