1975 Season 5 Episode 3 "Aftershock".
This episode reveals a skeletal corpse inside a wall behind a fireplace after an earthquake in the very home that the McMillans live in.

Yeah, that episode was sort of intense. Most of the episodes were more light hearted and "fun". That episode was more serious & dire.

I thought the scary episode was the one where Mac and Sally were having their whole house fumigated. They are knocked out and end up being trapped inside the house, and the phone lines have been cute. Of course the stuff they are fumigating the house with is deadly poison. I remember that one being really creepy.

The skeleton in the fireplace episode was Aftershock, my personal fave.
As a kid, I saw another scary one that started with a seance, where a ghost appeared and accused the widow of murder. "Evie, why did you kill me? Why did you murder me? Why?"
Marriage is between one man and one woman, to the exclusion of all others.

Yeah, this is where they were thinking about selling their house. An earthquake happend when they were throwing mac a birthday party, and a skeleton fell out of the wall. This is also the one were the greek emeralds were hidden in the wall and mildred was on the couch when the greek got killed who was looking for the emeralds.
On the Halloween one the satinist thought sally was a rencarnated priestis Serena that had to be killed for some reason. Sally received different gifts for each year(3) but gave them to mildred. Sally was kinda kidnapped by this doctor who was part of this satan pact. I only remember this stuff because I watched them 1,000 times or less;-)

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