Fallen Angel

Aiba Tsubasa has astounding mathematical powers. He has two younger brothers: Riku, a naive but kind-hearted university student, and Umi, who was born with a weak heart and has no way to be saved except through an organ transplant. In order to help Umi, their mother Takako, a gifted surgeon, had left Tsubasa and Riku who were still very young and sought refuge with a medical research facility. The facility is a shadowy organization which studies people with phenomenal powers in specific areas and repeatedly conducts unethical human experiments in an attempt to create scientifically superior humans. As time goes by, Umi has a successful transplant surgery. Tsubasa and Riku desperately try to protect their younger brother, who has slipped out of the facility to seek their help.