After Frasier gets annoyed but Martin's squeaky chair while trying to watch a documentary, he decides to be nice and oil his chair but accidentally knocks over the oil can staining the carpet.
Frasier of course is furious; thinking he dad did it on purpose, so Frasier moves everything out onto the balcony while his carpet is being replaced.
While Niles and Frasier are discussing his carpet, Martin's chair caches fire, and while trying to put it out, accentually knocks it over the balcony right in front of Daphne and Martin.
Martin and Frasier get into another argument because Martin thinks Frasier did it on purpose, which Frasier denies, even though he has never really liked the chair.
In the end Frasier does something really nice for his Dad, he gets his old chair replicated, which shows how much Frasier loves his dad.