The Enterprise encounters a space-dwelling creature, accidentally kills it, then must find a way to pry its posthumously-born child from the ship, which it sees as its mother, before they're all killed by its feeding on the ship's energy. Meanwhile, Dr. Leah Brahms arrives on the ship to investigate Geordi's modifications to the engines. To Geordi's dismay, she's nothing like the computer recreation of her that he worked with in the holodeck, back in Booby Trap.
Notes
The plot of this shares quite some similarities with "Booby Trap". In that episode, too, the Enterprise was stuck in place because its energy was being drained, at threat of lethal radiation exposure, and Geordi worked with Dr. Brahms to save them.
In this episode, both the crew of the Enterprise and the writers continue to try to come to grips with the holodeck. In "Booby Trap", Geordi developed a somewhat-more-than-professional relationship with the holographic Dr. Brahms, whose image, at least, was that of a real person. In 11001001, aired a couple of years earlier, Riker fell for a holographic woman, Minuet, who was wholly fictitious. Riker's interlude with Minuet is presented as basically positive, but in this episode...
Dr. Brahms (the real one) stumbles across Geordi's holodeck program featuring Dr. Brahms (the fake one) and is... perturbed. Geordi rushes in, just as Dr. Brahms watches the hologram saying something rather embarrassing:
Dr. Brahms (hologram): I'm with you every day, Geordi. Every time you look at this engine, you're looking at me. Every time you touch it, it's me.
Perturbed isn't a strong enough word for her reaction, actually:
Dr. Leah Brahms: Now... I understand.
Geordi La Forge: No, you don't. It's not the way this may look.
Leah: I called up a replay of the program file. I was all ready to compliment you again, Commander, for constructing a program which contained the prototype engine so that you would always have a baseline reference for your modifications. And now I find that it's all about a fantasy plaything.
Geordi: It's not like that. I swear--
Leah: I'm outraged by this! I have been invaded, violated! How dare you use me like this? How far did it go, anyway? Was it good for you?
Geordi: Nothing like that happened. It was a professional collaboration.
Leah: Oh, I can tell. "Every time you're touching the engine, you're touching me"? Real professional!
Geordi: Look, if you watched the whole program, you saw what it was. We were working together to solve a problem in a crisis situation.
Leah: How do I know how far it went? How many other programs did you create? Perhaps dozens of them, one for every day of the week, one for every mood!
Outraged, that's more like it--and she has reason to be. Oh, we can assume that it's as Geordi says, and there were no further programs, and we know from seeing "Booby Trap" ourselves that he hardly sat down and decided to program up a 'fantasy plaything', but Dr. Brahms isn't in our privileged position.
Still, if this had been the whole of Geordi's transgression, it wouldn't have been so bad. Bad judgment, sure, but not bad intentions. But here we see him taking that experience on the holodeck and using it to try to woo the real Dr. Brahms. Lying to cover it up. Persisting in his advances despite Dr. Brahms being pretty clear she wasn't interested. And, when confronted about it by Dr. Brahms, admitting to no error other than, he claims, offering her friendship. Geordi, I hate to break it to you, but I'm pretty sure it wasn't friendship that you were aiming for, there.
Keith R. A. DeCandido, in his rewatch of the episode, says that Geordi has been "turned [...] into an unrepentant virtual rapist". I don't know if that's exactly the right language, but the it's hard to disagree with the sentiment. Throughout the episode, besides insistently trying to turn their professional relationship into a personal one, Geordi repeatedly violates Dr. Brahms's trust for his (anticipated) personal gain. He definitely doesn't come off well.
The worst thing about the episode is that it takes Geordi's side. He makes his very dramatic (and spurious) claims of offering friendship to Dr. Brahms, then storms out, the scene ending on Dr. Brahms looking... repentant? Uncertain? Not outraged, in any case. And following that they patch things up and are best buds by the end of the episode. I'm sure that they weren't interested in making a villain of Geordi, and even making him definitely wrong in his use of the holodeck would be inconvenient, since they'd have to be much more careful with their use of it if there were some ethical guidelines people were expected to follow, but at least they could have indicated that he was definitely wrong in his treatment of Dr. Brahms. But it was not to be.