<P> The episode begins with Frasier writing a political speech for Woody, who has trouble doing it himself . Rebecca rejects plumber Don Santry's (Tom Berenger) proposal accidentally because she is too excited to accept it, causing him to break up with her . Sam struggles with his sex addiction and wants to avoid watching Kim Alexis on television . Diane Chambers, making her first appearance on the series after six years, appears on television, accepting an award for outstanding writing of a television movie, surprising Sam . Diane calls Sam at the bar to thank him for the congratulatory telegram he sent earlier . Diane accepts Sam's invitation to return to Boston, but Sam reveals to Norm that he doubts her confirmation . </P> <P> The following day, Cliff wants to be promoted by the head of the postal department, Marty Feldman, who often hires his own relatives rather than hard - working employees by merit, like Cliff . Frasier fails to correct Woody's grammar . Norm begs Woody to hire him as a city accountant . Rebecca arrives an emotional mess in the same dress she wore the previous day . Then Diane arrives with her "husband" Reed (Mark Harelik), surprising Sam . Sam uses Rebecca, who is grieving her love loss, as his pretend wife . At Melville's restaurant, when Don enters and re-proposes, Rebecca finally accepts in front of the others, ruining Sam's charade . After Rebecca and Don leave, Reed's partner Kevin (Anthony Heald) arrives to confront him for "cheating" with Diane, who clearly was not married . Now alone at the table, after Kevin and Don leave, Sam and Diane both come to terms with the fact they have no family of their own . Diane admits to Sam that she broke her promise to return to him after six months in the episode "I Do, Adieu" (1987). In fact, her manuscript was rejected by publishers but then became a television movie prompting her to stay in Los Angeles for six years looking for greater success . When Diane bids Sam farewell and is about to leave, he stops her and convinces her they should rekindle their relationship for old times' sake . </P> <P> The next day Woody gives Norm a job with the city . Rebecca marries Don but secretly regrets it, feeling he is too good for her . Cliff is promoted to postal assistant supervisor after giving Marty gifts . Sam and Diane walk in and announce their engagement . His friends disapprove . Having enough of their disapproval, and going years without a family, Sam leaves the bar with Diane . On the plane, they begin to reconsider their decision to be together again . As the flight is delayed, they return to the airport terminal and amicably agree to part ways . Diane goes to Los Angeles, and Sam returns to Cheers to see his friends again . While Sam and his gang celebrate the reunion, Rebecca announces happily that Don has a job with the sewer department and leaves excitedly with the tickets for their honeymoon trip . After the rest of the gang head home, Norm stays behind and tells Sam that he knew he would return to Boston for his "one true love", saying: "You'll always come back to her ." After Norm leaves, someone (Bob Broder) knocks on the door . Sam replies, "Sorry, we're closed," then walks over and straightens a picture of Geronimo in honor to Coach Ernie Pantusso hanging on the back wall, and then exits into the corridor toward the pool room . (In the original broadcast, after the closing credits, the text reads "Thanks for having us over on all those Thursday nights ." with the show's logo appearing .) </P> <Ul> <Li> ^ a Tom Berenger's character Don Santry first appeared in the previous episode, "The Guy Can't Help It". </Li> <Li> ^ b Time magazine implied the bar was Sam's true love . However, one television critic from the Corpus Christi Caller - Times said, "(T) he character Norm Peterson didn't tell Sam that the bar was his only true love . That sentiment was left to the viewer to surmise ." </Li> <Li> ^ c Bob Broder was an agent for the show's creators . </Li> <Li> ^ d See #Critical reviews . </Li> </Ul>

Who knocks on the door at the end of cheers