The story takes place in Tokyo's 20th ward  in a café called Anteiku. Some ghouls at Anteiku renounced killing. It's the home of some employees as well. Ghouls: bloodthirsty monsters. They can only digest human flesh and coffee. Ghouls and humans are different species. They can change the look of their eye between human and kakugan: red iris and black sclera.
Female ghouls don't like to be seen while eating.
Anteiku: gathering place of the 20th wards ghouls. They do take human customers as well.