The episode begins, as most noir-infused stories do, with a man on death row, giving a final interview before his execution - a little on the nose? Sure - but the episode has a good pedigree: It's based on a story by John D. MacDonald!
Okay, so here's the lowdown - John Heard is a man wrongfully accused of murder, and a sexy newspaper reporter is there to take down his side of the story. John, for his part, is just sad he'll never see his mysterious woman again - but who is she, and where has she gone? The prosecutor thinks she never existed, but why?
Which means that it's time to resolve them - through flashbackery! It seems that John is an inventor, and during an earthquake some months earlier (not years? This is a fast execution...) a mysterious volcano burst forth from his basement floor. Inside the stone? A ring-
While its origins were a mystery, the use of the ring wasn't - as he turned it the hole in the centre of the ring changed, becoming a gateway to a different dimension. Being a good scientist, John began sending probes into the hole, testing the environments on the other side - he found so many bizarre pieces of stone and art on the other side, that he made the questionable decision to bring a jeweler friend in on the caper.
You'd think with proof of intelligent interdimensional life he could have gotten a slightly higher-profile helper than a sleazy pal, but whatever. The jeweler is happy to see giant uncut rubies coming out of the hole, and wants John to dial the ring back to the jewel world, and just start scooping them out as quickly as he can. Which, in all honesty, is probably what I would do in his shoes - goes to show I really can't be trusted with magical interdimensional gateway technology, I suppose. John isn't cool with profiteering, however, and worries that it's too dangerous to mess with. Especially after something in one of the worlds tore through a steel cable!
John's best-laid-plans to shut down the experiment go awry when he pulls the cable up one last time, only to find Penelope Ann Miller (in her first TV role!) clinging to it!
She's a human-looking interdimensional creature, and although she's terrified by her surroundings at first, she quickly learns English and begins telling John about her bizarre world, while he teaches her about earth. It's all very heartwarming - and her name is Keena! She proves a quick study, and before long she's speaking English like a native. Back in the present the reporter points out the slightly creepy aspect of him keeping a woman locked up in his basement to 'protect her from the world', and she's got a bit of a point, considering that in the very next flashback we see John putting her to sleep using a music box and lullaby.
John insists it wasn't like that however, and that their love was chaste, damn it! It also turns out that her intellect and physiology were more alien than he first imagined. She can only eat frozen foods - and within a week of learning English she's already reading advanced science texts! You see, to her interdimensional brain, human science is extremely primitive - why, we can't even stop time or teleport matter! Before she can demonstrate any of the abilities his jeweler friend shows up, demanding the ring.
John is helpless to stop him, lest the jeweler reveal the secrets of the ring to the authorities! Penelope tells John not to worry - her people are super-advanced, and they'll be able to find her and bring her back to her own world quickly enough. John isn't just worried about her, though - what kind of damage might the jeweler do to the other dimension that he's strip-mining!
A visit to the jeweler's house reveals the consequences - he accidentally tore someone's arm off with his jewel scoop! The jeweler agrees to give it back, but before he can go through with the transaction, an interdimensional death cloud appears out of nowhere and squishes the jeweler into nothingness! This occurs off camera, of course. John then rushes back to his basement, and discovers that both Penelope and the volcano are gone!
With his friend squished and the ring taken away, John was left with no proof of what had really happened, and he was quickly convicted of murder. Although I'm not exactly sure how - yes, John was heard arguing with the jeweler on his lawn, and yes, there were some rubies and pieces of flesh scattered around the scene, but how on earth did the DA prove that John had made the man explode? Or crushed him to nothingness? Maybe he had the motive and opportunity, but what, pray-tell, were the means?
This is America, though, where people are executed for almost no reason at all, so John goes quietly to the electric chair, where the switch is flipped - and time stops! Remember how Penelope said she could do that? Well, she does, rescuing John from the death chamber and bringing him back to her dimension of pure thought and frozen food!
Well, that was just heartwarming, and not at all scary. How nice. Also, reading only Travis McGee books, I didn't realize John D. MacDonald wrote sci-fi. Oh, except for that book about the watch that stopped time. That was him, right?