Arisue Sei and Amamiya Rin are twins who were created in a laboratory as experiments. Separated while babies, they grow up to be polar opposites. When a virus breaks out on a small Japanese Island, Sei is sent to investigate where he discovers Rin. As the two come to terms with just who they are, they discover that the experiment, which was supposed to have ended years ago, is still occurring and that there are still many things being hidden; with them at the center.
A look into where we're headed with science, Yasha delves into the darkest recess of the human mind. Not afraid to ask, "What are we doing fiddling with the world around us?" we see the results through not only our eyes, but those who are a result. Well acted-you feel what the characters feel and the story nearly becomes yours-, tightly plotted so that nothing goes to waste, and as far from a romantic comedy as you can probably get, this show is perfect if you're looking for something thought provoking, gritty, and dark.
Bloody Monday and Yasha both deal with the topic of biological terrorism. They also contain a lot of edge-of-your-seat action scenes, and have extremely well done characters you will find yourself becoming attached to. If you love one, you will without a doubt love the other. (Also, just because Yasha is dated, don't let that dissuade you!)