So the plot against Nash unfolds. It's Lt. Ray Urbanski that's falsified documents incriminating Nash. What Urbanski has done is illegal, but the investigation is not. Rachel reveals the movement against Nash comes from the top - that the Mayor has authorized the Deputy Chief to investigate Nash. So this season finale leaves Nash between a rock and a hard place - he's on the outs with the SFPD. And Joe says he'd leave if Nash leaves.
And all the women leave too. Betty-Anne pulls a .44 Magnum on Nash, forcing Nash to mate with her. This is all over-the-top, but the entire Betty-Anne character and her super-efficiency at the SIU is all done for laughs anyways. Rachel self-destructs in trying to right the situation with Nash. She is caught breaking into Urbanski's office and we last see her in a holding cell. Cassidy decides to quit and leaves for Paris, presumably to visit her mom Lisa. Remember that Lisa works in Paris as a cook. But Paris, or far away places are like that, are banishment for characters in NASH BRIDGES. All the women let down Nash; and in the end, the Boys Club remains intact once again, as Nash is left alone with father Nick once again.
So a kind of scorched earth vision unfolds for Nash - the job has turned to crap, and all the women leave. It's what the cops call the one-two whammy - losing the job and the wife (or family) all in a short period. But NASH BRIDGES always walks the edge, and there is always the possibility of another one of those fantastic escapes or turn-arounds. Rachel could be cleared, Cassidy could return (not to the police force, but certainly from Paris to be Nash's lovely daughter once again), even Betty-Anne could return (we can see her super-efficiency effect on prison officials, who will be impressed enough to let her out to work in the SIU in a special prisoner furlough program). That's IF the show returns next season. If not, this apocalyptic Last Episode fulfills the destructive fantasy of a final end. But you can have you cake and eat it too, as this last episode leaves enough dangling to pick up for the next season if given the chance.
For more, see synopsis for Episode 122