Health inspector Mr Carnegie informs Basil and Sybil that the hotel is not up to par. He gives them twenty-four hours to rectify the situation, or the council may be forced to close them down. The staff get right down to tidying up.
While alerting Manuel to the situation, Basil notices that he is keeping a pet rat in his room. Manuel thinks he bought a Siberian hamster. Basil orders him to get rid of it. Polly offers to move it to a friend of hers, but really she and Manuel keep it secretly locked in a shed.
When the rat escapes back into the hotel after Manuel exercises it, a secret rat hunt is sparked. Polly, Manuel and Terry, try to find it before Basil gets wind of it. Unfortunately, Major Gowen spots it in the bar and gets his gun to shoot it. Basil spots him and finds out that the rat is loose. After confronting the staff, Basil joins in the rat hunt. In the kitchen, Basil puts a veal cutlet on the floor with some rat poison on it.
Mr Carnegie arrives and hears two gunshots. The major is in the bar with a shotgun and to shut him up, Basil knees him in the groin. Basil tells Mr Carnegie that the major was shooting at starlings. When Manuel gets the wrong end of the stick and believes that his pet rat, who is named Basil, has been put in a ratatouille, he goes into the kitchen and in the commotion a tray containing veal cutlets is upturned and mixed up with the poisoned one Basil placed on the floor earlier.
When Basil finds out that the poisoned veal cutlet he left on the floor has been mixed up with the others and that two cutlets are just on their way to the dining room, he has to come up with some ridiculous excuse as to why the diners cannot eat their lunch. To add to Basil's problems, Mr Carnegie has just finished his health inspection and wants veal for his lunch. The chef, Terry, decides to trim a piece that the cat was chewing earlier, as the cat is showing no signs of being poisoned. The veal is trimmed and served to Mr Carnegie. When Basil sees the cat vomiting he assumes that the veal he served must be poisoned so he takes it back. Sybil informs him that the cat was just coughing up a furball.
Manuel spots the rat underneath the table of a couple called Quentina and Ronald. Quentina feels uncomfortable by Manuel's staring, so Basil informs the couple that there is a bread roll under the table. The couple decide to dine elsewhere and Polly informs Basil that the rat is inside Quentina's bag. Basil digs into her bag and has to use the excuse of there being a bomb scare to explain his actions. The rat bites Basil and escapes into the dining room where Manuel catches it and puts it into a biscuit box.
When Mr Carnegie has finished his lunch, he asks for some coffee and cheese and biscuits. Polly opens the biscuit tin and the rat looks into the dumbfounded face of Mr Carnegie. When Basil faints, Manuel drags him out of the dining room. In an attempt to engage Mr Carnegie in conversation Sybil says, i'm afraid it's started to rain again.
Basil the Rat has a similar theme to that of The Hotel Inspectors. Both of these episodes deal with Basil's manic attitude to people in authority, people who have the power to thwart Basil's pie-in-the-sky ambitions of building the tawdry Fawlty Towers into something approaching respectability. In The Hotel Inspectors we don't see the Basil's dreaded authority figures right until the very last scene, but in Basil the rat we see the feared health inspector, Mr Carnegie, right from the off, investigating in the Fawlty Towers kitchen.
Unlike The Hotel Inspectors but similar to Gourmet Night, all members of the Fawlty Towers staff; this time: Basil, Sybil, Polly, Manuel and Terry are called upon to deal with the situation. Not only do they have to clean up the hotel, but they also have to track down Manuel's escaped pet rat before Mr Carnegie gets sight of it, and also prevent the health inspector from being served poisoned veal.
Unlike Gourmet Night, by the end of Basil the Rat everything seems to have gone to plan and Mr Carnegie, although bamboozled, seems to be none the wiser; although Basil has to be dragged out of the dining room by Manuel after fainting from the sheer exhaustion of it all.
The series comes to an end with Sybil engaging Mr Carnegie in small-talk.
[Basil trying to convince Manuel that his Siberian hamster is in fact a rat]:
Basil: Well, of course it's a rat. You have rats in Spain, don't you - or did Franco have them all shot?
[Basil getting infuriated with Sybil]:
Basil: Can't we get you on Mastermind, Sybil? Next contestant: Mrs. Sybil Fawlty from Torquay. Specialist subject - the bleeding obvious.
[Basil trying to comfort Manuel]:
Basil: Manuel... my wife informs me that you're depressed. Let me tell you something. Depression is a very bad thing. It's like a virus. If you don't stamp on it, it spreads throughout the mind, and then one day you wake up in the morning and you... you can't face life any more!
Sybil: And then you open a hotel
The hotel sign reads FARTY TOWELS.
The scenes with the real rat were pre-recorded. The only time this was done.
Melody Lang who plays Mrs Taylor was the real life wife of Andrew Sachs who plays Manuel at the time of filming.
Manuel's pet rat was previously mentioned in The Germans but not seen.
This, the final episode, was recorded six months after the previous episode because of a BBC strike.
Above the front driveway of Fawlty Towers is the sign Wooburn Grange Country Club. This is where the exterior shots were filmed. The director forgot to remove it before filming. This sign is also glimpsed in The Kipper and the Corpse and The Anniversary.
Mastermind was a highly popular quiz program in the UK which ran from 1972 to 1997 [see quote above].
Francisco Franco was the fascist dictator of Spain from 1939 until his death in 1975 [see quote above].
The Bubonic plague is a highly infectious deadly disease spread by bacteria cause by flea bites. Throughout the middle ages Europe
and Asia were ravaged by the disease many times.
Basil: Have you ever heard of the bubonic plague, Manuel? It was very popular at one time. A lot of pedigreed hamsters came over on ships from Siberia.
Basil mentions Wittgenstein when giving Manuel a simple task to perform. Ludwig Wittgenstein was an Austrian philosopher and one of the most
important thinkers of the 20th century.
Basil: It's not difficult, Manuel. This is not a proposition from Wittgenstein.