20 Million Miles to Earth

The XY-21 crashes into the Mediterranean Sea off the coast of Italy. Fishermen respond quickly, entering the nose-down craft through a gaping hole and pulling two spacemen from the sinking vessel before it vanishes beneath the waves. The rescue marks the first dramatic contact between Earth and the Venus mission survivors.

In Washington, D.C., Major General A. D. McIntosh confirms that the missing spaceship has been located and is to be recovered. He flies to the site to coordinate the retrieval with Italian authorities. The discovery triggers a cross-continental response to secure the astronauts and study the Venusian craft.

Pepe, a local boy, discovers a translucent cylinder marked USAF washed up on the beach. Inside it lies a gelatinous mass egg that quickly becomes the subject of scientific curiosity. He sells the strange find to Dr. Leonardo, setting off a chain of events that will bring Earth and Venusian remnants into contact.

Marisa, a third-year medical student, is summoned to tend to the injured spacemen. She travels with her grandfather, the zoologist Leonardo, to the site to provide medical care and observation. The gathering team begins to piece together how the Venus mission has returned to Earth.

When Calder regains consciousness, he discovers his crewmate Dr. Sharman is dying, joining the eight other crewmen who died in the crash or during subsequent events. The severe losses underscore the danger posed by the Venusian mission. The survivors brace for further surprises from the recovered vessel.

That night, the creature hatches from the egg and rapidly grows, prompting Leonardo to lock it in a cage for study and containment. By morning the being has tripled in size, escalating concerns about its nature and danger. The family and scientists debate how to handle this unknown lifeform.

McIntosh arrives in Italy with Dr. Justin Uhl and meets two Italian government representatives to report that the Venusian ship has returned. The officials begin coordinating a public response while trying to manage the growing media interest. The event marks the formal government involvement in the case.

Police divers begin to search for the sealed metal capsule carrying the unborn Venusian species. McIntosh offers a half-million lira reward for its recovery, triggering Pepe to reveal the capsule's location and that the mass he sold to Leonardo has become the source of the crew's latest discoveries. Calder and McIntosh resolve to pursue Pepe to recover the capsule.

The creature, now human-sized, breaks out of its cage and heads toward a nearby farm, where it terrorizes livestock and rips open bags of sulfur. The farmer is warned when the creature maims the dog, prompting Calder and others to reach the scene and trap the beast in the barn. Tension rises as authorities debate whether it is truly dangerous.

With permission to capture the creature alive, Calder devises a plan to ensnare it with an electric net dropped from a helicopter. Italian police join the chase, firing flamethrowers and rifles with little effect against a creature that has no heart or lungs and is driven by sulfur consumption. Sulfur is used as bait and the net traps the creature at a secluded site.

At the American Embassy in Rome, McIntosh briefs the press about the event, and the creature is placed in the Rome zoo for study. Calder explains that it is being sedated with a continuous electric shock for observation. Marisa begins to flirt with Calder as the danger continues.

A critical electrical short cuts power to the zoo’s containment equipment, waking the creature. It grows even larger and clashes with a zoo elephant, triggering a city-wide rampage through Rome. The beast's fury leads it from zoo grounds into the streets, destroying cars and landmarks.

Calder, leading a unit with bazookas, drives the creature to the Colosseum and launches a direct bazooka hit. A tank blast collapses the ledge where the creature clings, sending it to its death amid the ancient ruins. Marisa runs into Calder’s arms as the threat to Rome is finally ended.