Yasha tells the story of Sei and Rin, two twins who were cloned, and then were mysteriously seperated. Years later, the two meet. Sei grew up in America, and is now an bio-chemist. He is kind-hearted, and loves nature, yet his brother Rin is evil, and hates everything. The two must put there differences aside, and figure out who they are, and how they came to be in this thriller.