Intro: “What would you do if you thought someone from another world was watching you?” What do you mean thought?
Frederick Vanneck is chairman of the physics department at Cambridge . We are told that in his own voice coming from a spinning vinyl record; or maybe he is recording the record. Strangely, it is being played by a man whose head is hidden by a lampshade. There is just no reason for this as he just told us who he is. He gives us his curriculum vitae, but fears all his experience and fancy Latin will not protect him from ridicule over what he is about to reveal. If anything happens, he says, “This will be the only record [ha — nice pun!] of the strange events that started that evening in Cave’s shop.”
A man goes to the aforementioned curio shop owned by Mr. Cave to purchase the titular crystal egg in the window. Cave sees that the man is very anxious to buy the egg, so jacks the price up to 5 pounds. The man offers 1 pound and not one ounce more.
Not much of a negotiator, the man compromises at 5 pounds, but doesn’t have it on him. Lucky bastard — I’ve got a twenty spare pounds on me. After he leaves, Cave starts wondering why this unremarkable egg could be so valuable to the man. Rather than call, say, a geologist, lapidarist , or art historian Cave naturally calls a physicist to address the question.
Vanneck agrees to meet Cave much to the chagrin of his 28 years-younger girlfriend. Cave arrives with the egg and Vanneck quickly dismisses it as an ordinary crystal. After Cave leaves, however, Vanneck takes the egg into his lab where it begins glowing. Vanneck sees a vision in the crystal and says he is certain that “this landscape is not of this earth.”
Vanneck pulls an all-nighter from 11 pm to 9 am studying the egg. Cave calls at 9 am to check on the progress. He asks if he woke the professor, helping to explain why professors have such limited office hours. Vanneck blows him off and continues his research. He is able to more clearly see the landscape, and concludes by the rock formations and minerals that he is viewing another planet. Based on the position of Saturn in the sky, he determines that he is seeing a Martian landscape. Although Saturn is so large in the sky, it seems more like a view from Titan. 
Vanneck’s young girlfriend stops by, but his obsession with the egg leads him to throw her out too. Gazing back at the Martian landscape, Vanneck is shocked to have his view blocked by a one-eye-monster. Well, maybe he should not have been so quick to get rid of the girl.
When Cave comes to retrieve the egg, Vanneck shows him the landscape. He clearly does not want to give up the egg so when Vanneck’s back is turned, Cave grabs the egg and runs off. Vanneck does not pursue the 80 year old running with a heavy crystal egg.
Vanneck is in such hot pursuit of this priceless egg that he does not make it to the curio shop until after 1) Cave has been murdered, 2) it has been in the papers, and 3) the papers have been delivered. Cave’s wife says he was killed in an alley by thieves. Vanneck realizes he can tell no one of his findings without the egg as proof. He nevertheless tells his story, and is ridiculed by his colleagues.
Thinking he will gain credibility, Vanneck goes to see his publisher friend Walker. Walker greets him, “Vanneck, Vanneck, Vanneck!” Vanneck cheerfully replies, “Is there more than one of me?” Walker says, “Well, look at you — you’re fat enough to be triplets.” Vanneck tries to convince his “friend” to publish his paper. He has concluded that the Martian is watching us night and day.
Back to the record. Vanneck expects to be killed like Cave and implores others to take this as proof and to find the egg. There are gunshots and a hand breaks the record. The lampshade is a clumsy device but now makes sense if you think about it — but damn them for making me think.
Nothing really to recommend here. Blah episode based on a blah H.G. Wells story, cardboard sets, incredibly grating performance by Mrs. Cave. Egg is a pretty fair rating for this one.
-  What the hell? I expect an English setting occasionally on AHP, but there is just no reason to have this episode set anywhere but the USA. This aired just 6 years after the A-bomb was dropped — I think we had enough physicists to handle a crystal egg.
-  C’mon, lapidarist is not in spellcheck?
-  Saturn would be 10 times the size of our moon if viewed from Titan. In the excellent The Sirens of Titan, there actually is a one-eyed alien living there.
- Was Mr. Cave’s name a reference to Plato’s Cave? I’ll save you time — no.
- Available on YouTube, but why would ya?