Captain George Slocum (John Hodiak) and First Lieutenant Jerry Barker (Todd Karns) are longtime friends, assigned to the same US Army outfit in Korea during 1950, training South Korean army pilots in flying L5 observation planes. The L5's are slow-moving propeller aircraft, made mostly of wood and fabric and seemingly out-of-place in modern warfare -- but they're absolutely essential to military maneuvers and gunnery, even in the post-World War II era. George is sent to Japan just before Jerry's younger brother Pete (John Derek), also a pilot and a newly-minted second lieutenant, is due to arrive there. Pete is bold and brash, with his plane and his women, far beyond his early twenty-something age -- this gets him nowhere, either with hard-boiled nurse Audrey Totter or the brass, and he quickly reveals himself a to be a hot-headed screw-up who cannot follow orders or obey regulations. Slocum would like to take Pete under his wing, but the younger pilot isn't getting the message, and a day later North Korea invades its neighbor to the south and both men are ordered into combat. Their arrival at Kimpo Air Base -- where Jerry is stationed -- is a true baptism-of-fire, the field littered with bodies and wrecked aircraft and under attack by insurgents with automatic weapons. The wounded Jerry is killed before they can get him to safety, and only Slocum's cool head saves him and Pete, or their planes, which allows them to spirit two VIP passengers to safety -- and Pete nearly manages to turn that into a disaster as well. Slocum recognizes the emergency before them and wants everything done by the book, but Pete can't let go of the idea of revenge, and soon rigs his slow-moving low-altitude L5 plane with a bazooka, with which he plans to hit any targets of opportunity that come up on his observation flights. For his trouble he loses his plane and comes close to getting captured. Pete would be treading dangerously close to a court martial, but for the fact that their CO (Rex Reason) is desperately short of pilots. It takes a North Korean attack on their headquarters and its aftermath to get Pete to literally straighten up and fly right.