This interesting episode is about one scientist's plans to create a superweapon that will protect the world from foreign attack. A woman associate of his who is opposed to the creation of the weapon is discredited in the scientific community, so nobody believes her warnings of it being a mistake.

The surprise ending is simple, but it works well. Without giving it away, let's just say it reminded me a bit of a similar ending in the unrelated Twilight Zone episode "Third from the Sun".