Danny is soaring above Midston in a plane with his pilot friend when he catched sight of a man stranded in a field and helps rescue him. The man happens to be millionaire Gledway Pippit, who is interested in Professor Bullfinch's new heat ray -- but Danny and the Professor must prove to him that the invention can be useful. One afternoon, Danny's friend Irene is listening to her short-wave radio when she hears about a forest fire nearby. Danny realizes that the Professor and Mr. Pippit drove their cars in that direction. Soon the police spot the men -- but they are surrounded by fire! Danny things he knows how to rescue them and put the heat ray to practical use. But can he do it in time?