An older couple going through their 3/4-life crises turn to spiritual and physical respites. She turns to a psychic and he marries a girl half his age. But the spirituality is occultic hocum and the girl ends up sleeping with men her own age.
Meanwhile, one generation down, they are having their own 2/5-life crises. But this time they both dabble in the hopes of love outside of marriage with the addition of literature and art. He struggles to make good on the promise of his first successful novel and she wants to open her own gallery. But neither one succeed.
It's like there are no solutions.
"Sometimes the illusion works better than the medicine," the narrator says at the end of the movie. But in the end, the illusions fail as well. The writer thought that by being with the girl next door and stealing a dead man's novel, he could have it all. But he ends up looking back across the way at his own wife, and the dead man turns out not to be dead. The artist thinks that all she has to do is express her desire for her boss and borrow money from her mother, but her boss doesn't reciprocate her feelings and her mother doesn't loan her the money.
It was all an illusion: eternal youth, spirits or stars guiding the future, the notion of romantic love, the ability to express oneself through art. And how much good did any of it do them?
It's kind of a cynical message, given the bulk of Woody Allen's work.