The Strange World of Planet X

In a secluded laboratory near a small village in southern England, Dr. Laird and American physicist Gilbert Graham push massive electrical power into magnetic field experiments using equipment never designed for such loads. An accident injures another assistant, prompting a request for a replacement to be sent from the Ministry of Defence. Brigadier Cartwright is dispatched to investigate the incident and assess the risks.

Michele Dupont, a woman computer expert, accompanies Cartwright and helps to solve the power problem, stabilizing the system. Cartwright is impressed by her skill, though he and others recognize that the larger risks remain unaddressed.

Cartwright's report convinces Deputy Defence Minister Gerald Wilson to treat Laird's project as a top priority. He orders a full security team to be deployed, led by counter-espionage expert Jimmy Murray.

As the experiments proceed, the hyper-magnetic fields begin to affect the ionosphere, producing unusual weather patterns and threatening ships hundreds of miles away. The magnetic field also weakens Earth's protective shield against cosmic rays.

A sudden burst of cosmic radiation from deep space causes brain damage in a local man, turning him homicidal. The radiation also triggers mutations in the surrounding insect life, producing dangerous mutated creatures near the village and lab.

A mysterious, well-spoken visitor known as 'Mr. Smith' arrives in the village, offering warnings about the dangers of Laird's experiments. Murray suspects he is a spy, but Graham and Dupont judge that the immediate threat from Laird may be greater.

Despite Mr. Smith's warnings, the forest adjacent to the village becomes swarming with gigantic insects and other mutated monsters. Graham and Dupont's attempts to halt the project fail, and they decide to alert the authorities.

The army arrives to confront the escalating danger and investigate the mutations around the laboratory. Graham and Dupont help coordinate the response as the threat grows.

Dupont, fleeing the mutated creatures, is trapped in a spider's web. The army arrives in time to intervene and ensure her safety while they work to neutralize the threats.

Mr. Smith reveals to Graham that he is an alien emissary from a world called Planet X. He explains that Laird's experiments threaten not only Earth but his planet's orbit, and warns of the potential consequences if they continue.

Graham, Dupont, Murray, Cartwright, and Mr. Smith decide to stop Laird's dangerous project. They hurry back to the laboratory to confront him before more damage can be done.

Mr. Smith uses a handheld device to summon his flying saucer and positions it above the laboratory. The saucer fires rays that obliterate the building, averting the coming disaster.

With the threat averted, the alien bids farewell to Graham and Dupont and returns to his saucer, which ascends into the night sky.