Foreign powers keep getting their hands on U.S. military secrets, so the head of the American diplomatic corps calls in his nephew Dick Stansbury to help. Stansbury knows that Doctor Montell is at the bottom of this, so he poses as an inventor of an innovative aerial gun. This sparks the doctor's interest, and when they both attend a weekend party at the Ryerson estate, Montell tries to get Stansbury to sell the gun to his country.
Right after a husband and wife (Robert Edeson and Eulalie Jensen) arrive home from their honeymoon, the husband goes to fetch his sister from boarding school. While he is away, the wife's friend and neighbor, McGregor (Harry Morey), invites her to a party, and she accepts. On the way back home, they're involved in an accident, and McGregor takes the wife, who's unconscious, to recover at a nearby roadhouse. Unfortunately, McGregor's coke fiend brother (William R. Dunn) is there partying, and he threatens to put a seamy spin on the innocent situation and tell all.
Enemy agents under the leadership of "Emanon" conspire with pacifists to keep the American defense appropriations down at a time when forces of the enemy are preparing to invade. The invasion comes, and New York, Washington, and other American cities are devastated.
