Operation Terror (Unabridged‪)‬

Murray Leinster's science fiction stories typically dealt with themes of frustration with human frailty and its limitations, cynicism vs. idealistic ethics and romance. When a mysterious alien spacecraft lands in a lake in Colorado and the invaders begin using a parylyzing ray that no one can understand or stop, it takes an ingenious man like Lockley to save the girl and solve the mystery of the aliens.