Faith Domergue had a cold beauty that made her suitable as female scientist Professor Leslie Joyce. The stereotype of the cold, hard scientist whose intellect does not allow itself to be swayed by mere sentiment and feeling was especially prevalent in the old science fiction movies, and thus a beautiful female scientist constituted a special challenge for a macho man, used to having his way with ordinary women. In this movie, said macho man is Commander Pete Mathews.
A lot of old movies are sexist by twenty-first century standards, but science fiction movies from the 1950s, with their inevitable beautiful female scientists, often have a feminist theme in them, pushing back against that sexism. But the message tends to be mixed, with the movie expressing a sexist attitude one minute and a feminist attitude the next. No more is this so than in "It Came from Beneath the Sea."
Joyce's colleague is Dr. John Carter. They have both been called in to investigate a hunk of mysterious substance that got caught in the diving plane of Mathews' submarine. When Joyce definitively determines the nature of the substance, a piece of giant octopus, Carter kisses her on the cheek, and then she nestles in his arms as Mathews calls Naval Intelligence. If they were actually involved romantically, this would not be so strange. But they are not. As a result, we get that strange mixture of feminism and sexism: on the one hand, she is the expert in her field and has found the solution; on the other hand, she is a pretty girl that men just naturally kiss and hold in their arms, even when that man is a colleague in a professional setting.
On their last night in Pearl Harbor, they all decide to have dinner together at a restaurant. After Mathews and Joyce dance for a while, we think that Mathews is going to try to kiss her, but she moves her head forward and kisses him instead and then puts her arms around him. So, contrary to appearances, she is a sexually aggressive woman. Then they return to the table and have their meal. When Mathews realizes that Joyce still intends to go to Cairo to study the Red Sea with Carter, he is shocked. Presumably, he thought that since they kissed, she was going to give up all this foolishness about a career, marry him, and have babies. He leaves in a huff.
Their plans to go to Cairo, however, are foiled by the disappearance of a tramp steamer. In order to get the facts, a doctor examines the survivors. After the first survivor tells his story, the doctor decides he needs the care of a psychiatrist. The other three survivors, not wanting to be committed to a mental institution, deny having seen anything. They are given lie-detector tests, which show that they are lying about not seeing anything. And then the first survivor recants his story so that he can be released from the infirmary. Mathews and the other officers are exasperated and just don't understand why they can't get the truth out of these guys.
Professor Joyce rises to the occasion. Removing her coat so as to expose a little more of her soft, warm flesh, she tells the officers she will talk to the first survivor when he is released, and then contrives to be alone with him in a room. Using her womanly wiles—giving him sexy looks, touching his hand, showing a little leg—she gets the man to admit he saw the sea monster, which the officers hear through the intercom. So, you see, that's why we need female scientists, because they have special ways of getting to the truth.
Mathews and Joyce decide to investigate reports of poor fishing along the northwest coast, because it may be that the octopus has been eating all the fish. They spot what might be called an octopus footprint on the beach and they send for Carter. When Carter arrives with the deputy sheriff, Mathews asks Carter to help him persuade Joyce to leave and let the Navy take over the job. When Carter asks what Joyce has to say about that, Mathews responds, "What's the difference what she says?" At that point, Carter proceeds to lecture Mathews about women: "There's a whole new breed who feel they're just as smart and just as courageous as men. And they are. They don't like to be overprotected. They don't like to have their initiative taken away from them."
Joyce picks up the argument: "A, you'd want me to miss the opportunity to see this specimen, one that may never come again. B, you'd be making up my mind for me. And C, I not only don't like being pushed around, but you underestimate my ability to help in a crisis." Carter says that he is entirely on her side, as she nestles into the arm her puts around her. Mathews concedes to having lost the argument.
Suddenly, the octopus appears and kills the deputy, causing Joyce to scream like a girl.
The octopus starts wreaking havoc on San Francisco, Mathews and Carter take turns saving each other's lives, during which Joyce screams again, finding solace first in Carter's arms and then Mathews', until at last the octopus is killed.
They have dinner again. Mathews, saying that women can change, says he wants Joyce to marry him and start a family. She says she hasn't time for that and offers to collaborate with him on a book, "How to Catch a Sea Beast." Mathews tells Carter he is right about this new breed of women.
Review by disinterested_spectator from the Internet Movie Database.