This is a tasty piece of work and I can't do justice to it in a plot summary. But here goes.
The narrator, Gareth, is a gofer for Mr. Driscoll, a British crime boss. Today his mission is to drive a Jaguar down to a prison where the car's owner, Harry the Spider Linton, is being released after seven years for robbing a post office. Although, as it turns out, Harry thinks he owes his incarceration to the stupidity of Mr. Driscoll.
Harry's rage is so feverish that it seems like it might end the trip prematurely. Gareth might me in danger. What is going to happen if/when Harry gets to his old mate's mansion, and encounters the man he now sees as the cause of his lost years?
Well, I can't tell you that. But I will say that the ending sent a shiver down my spine, and it is a rare story these days that gives me a spinal freeze.