On the remote Petrie's Island, farmer Ian Bellows goes missing while walking home through the woods one night. His concerned wife goes to the locate constabulary, whereupon Constable John Harris heads out to locate the wayward farmer... only to discover him dead in a cave with his skeleton having been completely liquefied and sucked out. At his wit's end, town doctor Reginald Landers journeys to London to seek the assistance of his old friend, pathologist Brian Stanley (Cushing), fearful that a bizarre new bone-dissolving disease is running rampant on Petrie.
Along with Stanley's hunky bone expert colleague David West and West's rich girlfriend Toni Merrill, the gang travels to the island to investigate further, discovering that the sudden epidemic of boneless people and animals might in some way be connected to the work of reclusive cancer doctor Lawrence Phillips, who has set up shop in the island's requisite creepy Victorian-era mansion. As it turns out, Phillips and his assistants are all dead, and just as boneless as Ian Bellows.
The gang quickly realizes that Phillips' efforts to develop a Cure for Cancer have led to the creation of nigh-unstoppable silicon-based organisms called "Silicates" which live by eating bone matter, and soon Stanley, West and Toni are in race against time to find a means of destroying them before they overrun the entire island and kill everyone.
Not related to Terror Island.
Tropes used in this film:
- An Axe to Grind: Dr. Landers tries to use a fire axe to defend against a Silicate. It doesn't work. West later has to use the same axe to cut off Stanley's ensnared hand to save him.
- Anyone Can Die: Dr. Landers, a main character for the first half of the film (to the point where he's almost a Decoy Protagonist), dies at about the middle mark. Stanley himself almost falls prey to this trope, but some quick thinking on West's part (and an axe) saves 'im.
- Apocalyptic Log: Dr. Phillips' notes.
- Artistic License Law: The island's officer is consistently referred to "constable" Harris, a title that hasn't been used in Irish policing since 1922. Since there's no indication the island is under Northern Irish jurisdiction, he ought to be referred to (both officially and colloquially) as Garda Harris (or given his position, more likely Sergeant Harris.)
- Attack of the Monster Appendage: Type 2 example. When Constable Harris enters the test animal room, a green tentacle drops down from the ceiling and grabs him. Later, the same tentacle shoots out to try and grab the main characters, and, failing, the full creature emerges into view, giving us our first Silicate.
- Body Horror: All those boneless corpses.
- Chekhov's Classroom: The seemingly innocuous conversation Phillips and his assistant have at the beginning.
- Ditto Phillips' notes, which mention both the missing Great Dane and the fact it got an accidental dose of Strontium-90. The scene of the main characters discussing all of this is very brief, however, so if you don't pay attention you're liable to wonder about the significance of the dead dog Dunley finds. Fortunately, Stanley is there to remind us.
- Chekhov's Gun: The axe in the mansion. It's glimpsed a few times before Landers uses it in a failed attempt to kill a Silicate.
- Chekhov's Boomerang: After Stanley leaves the axe by the front door, it's forgotten about until West needs to use it to cut off Stanley's hand to save him.
- Chekhov M.I.A.: The missing dog alluded to in Phillips' notes. Also doubles as Chekhov's Classroom since it's only mentioned when West and Stanley are going over the notes.
- Closed Circle: Not only are they on an island, but a boat only comes once a week and the helicopter that flew them there has to leave early on.
- Combat Tentacles
- Cure for Cancer: Dr. Phillips accidentally creates the Silicates while attempting to develop a cure for cancer.
- Curiosity Killed the Cast: Several characters just have to go and see what that weird noise is.
- Dangerous Windows
- Darkness = Death: Which is why Stanley turns the lights on!
- Deadpan Snarker: Stanley.
- Dirty Coward: Halsey.
- Discretion Shot: Used whenever the Silicates suck out people's bones, mostly because they didn't have the budget to show it. The could show the aftermath, however... ick.
- Ditto the scene where Stanley's hand is hacked off, but only in the original British version. The American cut (ha) adds an insert of the hand getting hacked off, complete with splurting blood.
- The End... Or Is It?: The ending scene involving the Japanese scientist.
- Escaped from the Lab: The Silicates busted free from their tanks in Dr. Phillips' lab.
- Foreshadowing: The opening scene has Phillips' assistant Carson asking if they should wait for the teams in other countries to coordinate their experiments.
- It's mentioned early and often how the island is pretty much cut off from the rest of the world.
- Also the faulty generator and the flickering lights it causes.
- For Science!
- Getting Crap Past the Radar: Before the takeoff, our three leads have this... odd discussion:Stanley: What the devil did Napoleon do on that island of his to keep himself busy?
West: He invented solitaire.
Toni: [playful] I have a much better game in mind.
Stanley: Can three play?
[West smirks and shakes his head]
Stanley: [resigned] Fascinating game, solitaire.
- Gone Horribly Wrong: The scientists were looking for a cure for cancer.
- Immune to Bullets: And dynamite. And Molotov cocktails. And axes. And... pretty much anything really.
- Island of Mystery: Petrie's Island. Although during the daytime it's your normal Irish isle, it can be pretty creepy at night...
- Hell Is That Noise: The Silicates' weird electronic warbling.
- Horror Hunger
- Late to the Party: The helicopter pilot, who drops the main characters off on the island at the beginning, then returns at the end, having missed the entire adventure. He's probably thankful for that.
- Life-or-Limb Decision: See Anyone Can Die above.
- The Load: Toni.
- Mad Scientist: Averted. Dr. Phillips is a perfectly well-intentioned, albeit careless, scientist working for the betterment of humanity.
- The Main Characters Do Everything: West and Stanley more or less take over towards the end, doing all the important stuff, while the ostensible actual head of the island, Campbell, is relegated to a supporting role.
- My Car Hates Me: Your typical "engine stalls during a monster attack" scenario.
- Officer O'Hara: Constable Harris has some traits of this. It's okay, though, since the movie is set in Ireland, after all.
- Our Monsters Are Weird: The Silicates.
- Phlebotinum Muncher
- Picky People Eater
- Reasonable Authority Figure: Island "boss" Roger Campbell.
- Science Is Bad: One of the more noteworthy aversions; the heroes are men of science, doctors specifically, and they never once condemn what Phillips was trying to accomplish. Even when Campbell bemoans the fact Phillips ever came to the island, West is quick to point out the man only ever had good intentions. And, in the end, it is science that saves the day and kills the Silicates.
- Scream Discretion Shot: When Ian Bellows wanders into the cave, we don't see what befalls him, just his horrible screaming.
- The Siege: The heroes find themselves trapped inside the town ball, and later the clinic, besieged by the Silicates.
- Silicon-Based Life: The Silicates.
- Spiritual Successor: Night of the Big Heat, another Planet Films Sci-Fi Horror production starring Peter Cushing, directed by Terrence Fisher, and set on a remote island. It released a year after this film.
- What Happened to the Mouse?: Where did Dunley disappear to during the climax?
- The X of Y