Well, basically a man wants to murder his mistress because she wants him to leave his wife. He doesn't so much want to as sees no way out.
I like the fact that he's an opthamologist and seeks advice from a rabbi who's going blind.
The rabbi is the brother of Woody Allen's wife. Woody and his wife (I forget their characters' names) have been platonically married for a year. He meets a producer who is working with his wife's other brother, Alan Alda, an obnoxious but successful television something-or-other. That's Mia Farrow.
So Mia and Woody seem to genuinely hit it off. But then Mia goes away for a while on business and Woody splits up with his wife. But when Mia comes back she's engaged to Alda.
There are maybe four or five moments where there is really melodramatic dialogue that segue into film footage as watched by Woody and someone else (his neice or Mia or someone). The movies seem to mimic the dialogue that directly preceded it. And in one ocassion, Woody says: "This only happens in the movies," as if acknowledging the melodrama he's pitching at us.
On some level, we are expected to accept this as reality. At the end there's a big wrapping up where someone says that life isn't structured to include human happiness and maybe our only hope is in the future. So that these mistakes, the crimes and misdemeanors we have been witness to, are indicative of current morals. I'm not even going to bother trying to explain who that someone is.
But on the other hand, it's a movie, and Woody never wants us to forget that.
I find this film to be a disturbing turn for Woody. He'll return to this theme of killing off your problems, and it is a dark and foreboding undercurrent.
Obviously, Woody isn't advocating the behavior he depicts. At the end of the movie he says that if he were making the movie, he would have the guy confess because then it would be tragic.