This is another of the atomic-monster genre, which, coming at the end of 1955, was not particularly new. Them ('54) had kicked off the sub-genre of monsters created by radiation. Beast from 20,000 Fathoms ('53) began the sub-genre of the already-existing "monster" being released by nuclear activity. Creature from the Black Lagoon ('54) was the debut of man-sized rubber suit monsters. Phantom of 10,000 Leagues, (P10K) is a weak coat-tailer of Black Lagoon, but added little. What it did was combine the radiation-spawned monster with the man-sized rubber suit monster sub-genres.
P10K is typical of low grade B-movies in having adequate, but unremarkable acting, minimal sets and minimal effects. The plot does not venture very far at all into the science part of science fiction. What little explanation is offered goes by too quickly. Instead, it's more of a murder mystery with vague spy story undertones. The inspectors inspect clues and suspect suspects to solve the murders. This, and a rather plodding pace, make P10K a weak example of sci-fi, but passable as a mystery story.
Quick Plot Synopsis
A fisherman is pulled under by a mutant beast. He washes ashore, dead of radiation burns. A Dr. Stevens and a Mr. Grant, a government investigator are seeking answers. A Professor King recently set up his Pacific College of Oceanography. It turns out that the professor had "activated" a uranium deposit on the sea floor in hopes of creating a "death ray" with the heavy water. The professor's assistant is after the secret of the professor's work. Dr. Stevens and the professor's daughter, Lois, start up the obligatory romance thread. When a freighter travels over the radiation beam and is destroyed, the deaths prove too much for the professor's morals. He resolves to fix matters. He rows out to sea and scuba dives to the uranium deposit and "phantom" with some dynamite. He blows up the deposit, the monster and himself. His terrible weapon secrets died with him. The End.
Why is this movie fun?
The monster plays into the story very little, actually. As a murder mystery story, P10K has a little merit. The mysterious professor, the suspicious assistant. Even Dr. Stevens seems shifty at times. The murder-mystery plot is complex enough to keep a little interest. The stereotypes are interesting to track. (see Good Girl / Bad Girl below)
For so-bad-it's-fun action, it is fun to see how there's never anyone on the beaches but the actors. Everyone rows out to the monster spot in a small row boat -- just the right size for tipping over. The phantom isn't very phantasmic. What seems naggingly obvious, is that despite the title, all the underwater action takes place at a depth of only 10 or 20 feet. Scuba diving had some public fascination in the mid 50s, so it only took a little underwater filming to captivate audiences. While not a genre starter, P10K is one of the early man-in-rubber-suit monster flicks.
Cold War Angle
P10K is more of a cautionary tale about atomic power and dangers, than it is about the Cold War specifically. There is a shadowy "them" which send the spies, George and Wanda, to uncover the professor's secrets. "They" are never named. The fact that the project was a super-weapon vaguely hints that it was a competitor nation, though this is never developed. 50s audiences already knew who "they" were.
Cautionary Monster -- As would become more commonplace, P10K is one of those stories intended to warn people about the dangers of atomic energy. As much as we might want it for a weapon, its dangers might get us too. The "monster" itself is a personification of radiation. It kills when you get near it. At the end, the customary moralizing moment, Lois says, "I knew he wanted this power to help humanity, not destroy it." Dr. Stevens responds, "Nature has many secrets which were not meant to be understood. That's why he took his secret with him."
A Little Cheesecake -- There are a couple scenes which do nothing to advance the plot, but appear to be thrown in simply for exploitive motives. One such scene has Lois in the shower, her suggestive silhouette on the shower curtain. This is followed by a few dressed-in-towel views until Dr. Stevens helps her get into her tight-fitting dress. Pointless, but probably perked up the young men in the theater. A second serving comes when George meets platinum blonde Wanda on the beach. She lounges, pin-up style in her frilly strapless bathing suit. The camera views are optimal for showing off her feminine charms, but do nothing for the plot. They're just a couple random servings of cheesecake.
Good Girl / Bad Girl -- Lois, the professor's daughter, is clearly the "good girl". She's the loving daughter. She's the single and available young beauty who apparently has nothing whatsoever to do but lounge on the beach or on the patio. Wanda, on the other hand, is just as clearly the "bad girl." She has floozie platinum blonde hair and swaggering attitude. She's apparently "been around" and unstable in relationships. She's a tool of the mysterious "them."
Shadow of Godzilla -- A few parallels to Godzilla stand out. One, the creature is T-Rex-ish, like Godzilla (though man sized, not 100' tall). Two, the creature was spawned/awakened by radiations -- weapons research. Three is the deadly atomic beam which sinks the ship. Very Godzilla-like. A fourth similarity is how the genius scientist must give his life to stop the monster.
They're NOT after our women -- The poster shows a larger monster grabbing a woman diver by the thighs and staring at her chest. Thankfully, no such scene appears in the P10K. The creature grabs the professor when he goes down with the dynamite, but no women.
Poor Naive Professor -- Professor King plays the typical (almost cliche) role of the naive (misguided) scientist. He "activates" an undersea uranium deposit, which produces a powerful beam. This could be a super-weapon (a fact not lost on the two spies). As his daughter Lois says at the end, however, "I knew he wanted this power to help humanity, not destroy it." Professor King, like many naive scientists, gives his life (tragic hero style) to stop his monstrous creation.
Bottom line? P10K is a lower B grade of sci-fi that follows customary plot threads. It will likely anger or frustrate viewers looking for thoughtful (or active) entertainment. For nerdy fans of 50s sci-fi, however, the stereotypes themselves are kind of fun to watch.