It is the morning of Basil and Sybil's fifteenth wedding anniversary, and Basil has made some special arrangements in order to surprise Sybil. Some of her friends are coming over, and Manuel is going to cook his mother's special paella.
Basil decides to pretend that he has forgotten about their anniversary, and when Sybil drives away in a huff, Basil is left in the car park with his guests just arriving.
With two of his guests, Alice and Roger, having arrived, Basil and Polly come up with the idea of Sybil being ill in bed in order to explain her absence. When more of Sybil's friends arrive, they are sure that they saw her driving in town. Basil assures them that it was a northern woman who bears an uncanny resemblance to Sybil.
With one of the group, Roger, still sceptical that Sybil is ill in bed and thinking that they have just had a row, Basil comes up with the idea of taking them upstairs with Polly disguised as Sybil so that they can say hello to her. Polly eventually agrees to the stunt at a price.
The guests finally go into the darkened room to see Polly in Sybil's sunglasses and wig lying in bed. Because of the darkness, two of the contingent trip and injure themselves. Basil has to open the curtains slightly to let in some light. One of the group, Virginia, who is a former nurse, wants to get a closer look and gets a punch on the nose from Polly for her troubles.
The guests come downstairs with their injuries and Basil is just about to say goodbye to them when Sybil turns up wanting her golf clubs. Basil introduces her as the northern woman and escorts her into the kitchen, where Manuel and Terry are fighting on the floor about who will cook the paella, and into a cupboard. Basil comes into the lobby to say goodbye to his guests. Polly descends and Basil says, piece of cake. Motioning his entry into the kitchen to deal with Sybil, he mutters, now for the tricky bit!
Basil forgot his and Sybil's wedding anniversary last year, and this year, as a nice surprise for Sybil ( or probably because he wants to rub Sybil's nose in it ) decides to throw a party with all her friends invited without telling her about it. Basil shows obvious enjoyment while feigning forgetfullness of the significance of the date as Sybil displays deep sadness that he has forgotten again. Of course, Basil's plans backfire spectacularly when Sybil storms off.
With all of Sybil's friends arriving, Basil could come clean and tell them the truth, but that would be too easy. Instead Basil has to go through with the ridiculous charade of dressing Polly up as Sybil and pretending that she is ill in bed to get himself out of yet another embarrassing situation. Sybil even comes back to the hotel at one point pouring her heart out to Basil, but his monomania is too focused on embarrassment mitigation to be bothered by such trifles.
In The Anniversary, one of Basil's contingent of guests, Roger, seems to know exactly what Basil is up to from the moment he arrives, and he takes great delight in winding up Basil to breaking point with a series of well aimed barbs. Roger seems to be the only character, apart from Sybil and Polly, in the whole series to be truly cognisant of the inner workings of Basil's manic mind.
[Ex-nurse Virginia inquiring about Sybil]:
Virginia: Has the doctor been in?
Roger: No, but the dentist's had a good look.
[Basil explaining what's happened to Sybil]:
Basil: Look, it's ... look it's... it's perfectly Sybil. Simple's not well. She's lost her throat and her voice hurts.
[Basil trying to get Polly to dress up at Sybil]:
Basil: I'll ruin you...you'll never waitress in Torquay again!
The mixed up sign for The Anniversary reading FLOWERY TWATS, is the only true anagram of Fawlty Towers in the series.
Ken Campbell was a last-minute replacement for Roger. Due to a BBC strike, the original actor, Julian Holloway wasn't available.
Due to the strike extra rehearsal time was made available. John Cleese named it as his favourite episode.
Only appearance of Sybil's often mentioned friend Audrey.
Basil and Sybil's wedding anniversary is revealed as 17th April.
Only episode where Manuel doesn't utter the word "que?"
Basil and Sybil's bedroom is totally different to the one they had in The Wedding Party.
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 Basil the rat.
The Anniversary Party is meant to be at night, with paella for dinner. When Basil comes out of the kitchen, Ms Tibbs and Ms Gatsby greet him with "Good Morning Mr. Fawlty".
Oscar Wilde was a playwright and author known for his clever one-liners.
After Roger makes some quips.
Basil to Roger: You read a lot of Oscar Wilde, do you, Rog?