An educational film about bats. A scientist in a lab coat carries out experiments about bats sonar sounds. He picks up one bat out of a box/ cage, has guides its flight to a microphone. Then the scientist stands in a room full of flying bats and microphone. The bats mouth is tied shut and then put into a flying obstacle course. He falls and hits walls without his sonar. A shot of military radar satellites fades to a CU of a bat face. Shot of bats flying in the sky and out of caves.