The 27th Day

In The 27th Day five people from both sides of the Iron Curtain suddenly find themselves aboard a spaceship. An alien gives each of them a capsule which contains a weapon of mass destruction. The use of just one of them, or perhaps just the threat of using one, can start a nuclear war.

In 27 days the weapons will be useless. By that time either the human race will have destructed itself, which means that the aliens can overtake the planet or peace has been kept and so the human race has deserved the right to live.

Like so many sci-fis from the 1950s, The 27th Day is also less about aliens from outer space than about the Cold War and the paranoid, anxious atmosphere at the time. Not in the league of classics like "Invasion of the Body Snatchers" and "The War of the Worlds".