The male is a physiologist. His patient is a female and she has BPD, depression, and also DID (dissociative identity disorder)People refer to the girl as crazy because she enjoys torturing people but not killing them fully.
She was put into a mental facility in 2016 and has been there ever since.
The boy had been a physiologist since 2018 and he had problems of his own but continued to deal with him.
Eventually, They both get fed up and things turn cold for the city.