Airmail pilot Bob Lee (James Flavin), owner of a gold mine, faces off against "The Black Hawk" who has kidnapped Jimmy Ross (Al Wilson), Bob's best friend. The Black Hawk carries out a series of attacks on Bob's ore shipments by air. He uses an unusual catapult that launches aircraft into the sky to intercept Bob's aircraft. With Mary Ross (Lucile Browne), his sweetheart, Bob constantly battles against his enemy, and eventually is able to defeat him.
The Airmail Mystery was Universal's first aviation serial and it set the pattern for the serials and feature films to follow.
Al Wilson worked together with stuntmen like Frank Clarke and Wally Timm and also for movie companies, including Universal Pictures. After numerous appearances in stunt roles, he started his actor career in 1923, with the serial,The Eagle's Talons. He produced his own movies until 1927, when he went back to work with Universal. Wilson was also one of the pilots in Hell's Angels (1930) and during filming, he was involved in an accident where the mechanic Phil Jones died. This episode marked the end of his career as stunt pilot in movies, although he continued to work as an actor. 
Wilson's last role was in The Airmail Mystery. After production was complete, during the National Air Races in Cleveland in 1932, Wilson's aircraft crashed and he died a few days later in hospital due to the injuries he suffered. The accident is documented in the film Pylon Dusters: 1932 and 1938 Air Races, an historic film about the 1932 Cleveland Air Race.