Frustrated by heavily overcast skies that make precision bombing impossible, the Allies are at wits' end, until Dr. Rink, a civilian master technician (Burgess Meredith), arrives with a new, top-secret technology enabling the 918th B-17s to bomb accurately through the clouds: airborne radar. The first missions employing the device are wildly successful, especially since the Germans cannot effectively intercept the bombers with fighters or anti-aircraft fire due to the cloud cover. Unfortunately, the Germans quickly devise a countermeasure that actually uses the signals from the device to trace the bombers, allowing them to pinpoint the Americans with deadly accuracy. Only Dr. Rink has the knowledge to turn the tables once again, but he is virtually catatonic at the apparent failure of his technology.