The USA's sorry state preparedness following the surprise Japanese attack on Pearl Harbor leads the War Department's super secret "Department of Special Projects" to search every backyard in the country for any weapon, no matter how hare-brained, that might turn the tide against the Japanese onslaught. But even the D.S.P. couldn't foresee the disastrous consequences, when an overzealous Lieutenant sells them on Professor Flungk's "Flying Boomerang." It's an airborne nightmare, but even FDR is touting the new secret weapon in his fireside chats. The notorious "Flying Boomerang" is going up against the best the Axis has to offer, even if it is more deadly to its own crew than to the enemy.