Here is the short pitch.
Each morning he has breakfast with his wife’s ghost (he knows it is a grief hallucination). He meets a woman and that is in the early stages of a romance. The cops come and tell him her murder is now a cold case. The man that runs his local shop is killed during a robbery.
He now decides to use his job as a taxi driver, a job that goes always unsure. To find people that deserve punishment and dispense some justice.
This brings the police into his neighbourhood. This fuels his rage. His wife is begging him to stop. To go seek help. But getting help will mean he will never see her again.
His new romance calls the cops.
The story ends with him letting himself be shot by the cops. He realises he has become part of the problem. He will also get to see his wife again.