Kaneki Ken, a Half Ghoul, and Half Human. People in this world despise ghouls because of the fact, they feast on humans. Kaneki one day encounters a lovely lady by the name of "Rize". They both share the same interests, but soon finds out that she is a ghoul. 
As she tries to feast on him, they get squished by a crane. Being the only one barely surviving, Rize's ghoul organs were transplanted into Kaneki. Now trying to live a life of a human, and a ghoul, he now understands both worlds. 
He's confused, and changing from living a normal human life, he goes to being a flesh eating monster...