Frasier invites Diane to his apartment to catch up. Diane manages to inadvertently insult Martin by asking him how he's doing while speaking condescendingly to him
"Since you saw me last my wife died, I got shot in the hip and I have to live with Frasier because I kept falling down in the shower."
"Oh dear, I'm sure everything will be alright" Diane replies then pats Martin on the leg.
"That's the bad one." Martin says sarcastically
She also insults Niles by asking about the strange little lady that had eaten everybody's sorbet then had to have the coat check woman massage her abdomen she had met earlier
"Oh dear, don't tell me you married her and lived happily ever after."
Niles replied: "No can't say as we did."
During dinner Diane rattles on about how great her life has been. They get up to her being in Seattle and Diane begins to talk about her play then develops a
"large tick or a small seizure" per Daphne.
Diane confesses she is unhappy and needs Frasiers help. The backer for her play pulled out.
That afternoon while in conversation with Niles, Frasier confesses that he is still in pain from Dianes leaving him at the alter.
The next day over coffee Niles listens while Frazier confesses he is backing Dianes play
"It's tax deductable." Frasier continues to babble on explaining and justifying his re-involvement with Diane, accusing Niles of being a busy body when in fact Niles is saying nothing at all.
Later that day when Diane is at Frasier's apartment, she invites him to the dress rehearsal as a means of paying him back for his kindness.
"Be the first to see my play"
Frasier accepts as Diane goes into the bathroom to freshen up. Martin walks into the living room just in time to hear Diane say
"Tonight I give myself to you"
After a few more sentences with sexual undertones, Martin runs into the kitchen shouting
"People still in the house."
At the dress rehearsal it is obvious the characters in Diane's play are based on the locals of Cheers and the play is bad. The Frasier and Diane characters are written to be friendly. When the Frasier character makes reference to being left at the alter, the reply is
"I know you have forgiven me for that."
The real Frasier sitting in the audience reacts with shock and amazement.
When the character Frasier states that he is not sure what he should be feeling about Diane's character Frasier shouts from the audience that he can help. After an aggressive and angry retort that refers to Diane as the Devil that he cannot get away from no matter how far away he travels and no matter how much time has past, Frasier storms off the set.
But returns a little while later to apologize for his outburst and tells Diane that he really doesn't think she is the devil. Diane confesses that the play is not ready and they reach an understanding. Frasier exits through the fake bar door,
"Sorry, force of habit."
And the show ends.