The Show Must Go Off is the twelfth episode of season eight.
Frasier and Niles try to revive the career of a beloved actor from their childhood, but, all too soon, they discover that they've made a terrible mistake.
While visiting a sci-fi convention to buy comics for his son, Frasier runs into Jackson Hedley (played by Derek Jacobi), an actor he and Niles saw perform a one-man show series of Shakespeare monologues when they were in high school, sparking their love of Shakespeare. Hedley has since co-starred on a sci-fi show called Space Patrol as Tobor, the ship's android, and keeps getting typecast in similar roles. Later, discussing the matter with Niles, Frasier suggests that they rent a theater and have Hedley perform the Shakespearean monologues again, bringing his theater career back to life.
After renting a small theater, getting Jackson on board and starting the sale of tickets, they bring Jackson to the stage to help him get into spirit. Unfortunately, as he starts reciting Hamlet's monologue from Act 5, Frasier and Niles realize that his acting is hopelessly hammy. Thinking the years on Space Patrol has made him rusty, Frasier procures a video recording of his one-man show from their high school years, intending to show it to him and bring back his acting skills. Unfortunately, as the Cranes watch his recital of King Lear, they discover that he was as awful then as he is now and they were just too young to know it. Since the show will become humiliating for them and Jackson alike, Frasier and Niles plan to shut down the show, blame the director and refund everyone's tickets. When Jackson arrives at Frasier's apartment, however, he tells them that he has fired the director. Unable to tell Jackson how bad he is, they say they are worried that his rehearsal time has been too short. Sadly, Jackson thinks they are simply getting cold feet and wants to continue.
On opening night, Frasier and Niles are more worried than ever that their full audience will be disappointed. Realizing they may have exceeded their legal maximum capacity, they call the fire marshal to have the show cancelled. Unfortunately, he is occupied elsewhere and will take a while to get there. Backstage, they meet Jackson's father, Cecil Hedley (played by Patrick Macnee), who claims that he is Jackson's lucky charm and that Jackson always refuses to go on stage if he isn't present. Sadly, when they tell Jackson, he is overjoyed, having always found his father judgemental. Then, the fire marshal finally arrives and confirms that the theater is overcrowded and tells them to shut down. However, he turns out to be an avid Space Patrol fan and allows the show to continue, if he can stay and watch. Finally, Frasier tries to get the show stopped by setting off the sprinklers, but they won't go off. Luckily, just as Jackson is about to get on stage, he slips and breaks his leg. Thinking Jackson will quit, Frasier goes on stage and starts to announce that the show is cancelled on account of his injury. Behind him, Jackson, his leg broken, drags himself onto the stage to perform. Left without options, Frasier opens the show and lets Jackson begin, hamming it up horrendously and chewing the scenery without mercy.
Frasier, Niles and one of the stage hands watch Jackson perform. Unable to stand it, Frasier asks Niles and the stage hand for ear plugs. When neither of them has any spares, he walks away, covering his ears.
The episode taps into numerous elements of "Star Trek" lore, particularly the idea that Leonard Nimoy was better than his role as Spock allowed, and also that Brent Spiner is more than simply Data.
Jackson Hedly (portrayed by Derek Jacobi) plays a hammy, terrible Shakesperian actor. Sir Derek Jacobi is actually a knighted, multi-award winning theatre actor, and won an almost ironic Emmy for his betrayal of Hedley.