The 27th Day

Five people are abducted to an alien spacecraft in Earth orbit. The Alien explains his world is about to go nova and they are tasked with preventing humanity from destroying itself by using three capsules each. The capsules can obliterate all life within 3,000 miles, but only the owner can open their case with their thought waves, and they must be used within 27 days or become inert.

The five are returned to Earth. Evelyn Wingate discards her capsule by throwing it into the English Channel, and Su Tan chooses to commit suicide; her capsules self-destruct. The remaining three carry on with their lives, knowing the capsules are still active for 27 days.

The Alien hijacks Earth's communications and reveals the existence and power of the capsules to the world. Panic spreads as governments and people realize a single person could trigger mass annihilation. The capsules are now a global threat rather than a private weapon.

Klaus Bechner is struck by a car while crossing a street in Los Angeles and is taken to hospital, delaying his involvement with the crisis. Pvt. Ivan Godofsky is detained by his Soviet superiors for questioning about the aliens and their capsules. The tension between East and West escalates quickly.

Evelyn Wingate arrives in Los Angeles and is greeted by Clark, who is now in disguise. He escorts her to a closed, secure race track where they can hide from authorities and curious eyes while the crisis unfolds. Their cover allows them to avoid immediate detection while the world reacts.

A Soviet general interrogates Godofsky to extract details about the aliens and the capsules. Godofsky remains vague, shrouding the plan in mystery, which fuels Soviet urgency and suspicion. The interrogation signals the start of a global propaganda and security campaign.

Panic over the Alien's broadcast grows, with governments cracking down and civilians terrified of annihilation. Bechner is subjected to threats and two Communist agents nearly succeed in killing him, highlighting the stakes of the capsule secret. He refuses to reveal the details of the plan.

An innocent man who resembles Clark is killed by a mob amid the chaos from the global crisis. The real Clark and Eve work in the shadows, trying to evade capture while the political situation intensifies. The incident underscores how fear can masquerade as fanaticism.

Clark and Eve disclose their true identities to authorities and are taken into government custody to explain the capsule threat. Their testimony becomes part of the broader effort to understand and respond to the alien challenge. The containment and information drive the world toward a coordinated response.

Using sodium pentothal, Godofsky reveals the Alien's plan and the capsules' role to Soviet investigators. The revelation heightens global anxiety and demonstrates the power the capsules hold, prompting the Soviets to leverage the situation for harder bargaining. The capsules become a strategic instrument in East-West tensions.

A dying volunteer is left on a raft just within the 3,000-mile limit, while the US Navy destroyer that delivered him sits beyond it. An Admiral reads the coordinates and the subject is vaporized, a stark demonstration of the capsules' power. The event convinces the West to withdraw its forces worldwide.

Bechner studies the remaining capsules and discovers an imprinted mathematical code that can be used for both life and death. The discovery suggests a built-in mechanism to calibrate the capsules' effects depending on the command. The stakes are raised as both sides anticipate last-minute action.

As the Soviet general prepares to unleash the capsules, Godofsky intervenes and knocks the capsules from the general's hands. The capsules fall to the ground two stories below, preventing an immediate usage. Bechner then launches his own capsules, initiating the final countermeasure.

Bechner launches the countermeasure and triggers a high-pitched sonic wave that blankets the Earth, selectively killing every 'known enemy of human freedom.' The world experiences a sudden, unifying threat that galvanizes humanity to act in concert. The conflict resolves with a new sense of shared responsibility.

Humanity, unified under the United Nations, extends an invitation for the alien race to coexist peacefully on Earth. The Alien accepts the invitation, signaling a hopeful future where Earth and the visiting species can share the planet. The film ends with a dawn of a new era for humankind.