The wealthy lawyer Dick Russell (John Howard) funds the dotty old inventor Professor Gibbs (John Barrymore) to create an invisibility device. The first test subject for this machine is Kitty Carroll (Virginia Bruce), a department store model who had been fired from her previous job. The machine proves quite successful, and Kitty uses her invisible state to pay back her sadistic former boss, Mr. Growley (Charles Lane).
While the Professor and the invisible Kitty are off visiting the lodge of the millionaire Russell, the gangster Blackie Cole (Oscar Homolka) sends in his gang of moronic thugs (including Shemp Howard) to steal the device. With the machine back at their hideout, however, they cannot get it to work. By now, Kitty has returned to visibility, and the thugs are sent in to kidnap her and Gibbs. However, she has learned that some alcohol will restore her to invisibility, and uses this to defeat the gang (with help from Russell).
At the end of the film, it is revealed she has married and become a mother. To top it off, she and the professor learn that her treatment has apparently become hereditary, as her infant son vanishes upon being rubbed with an alcohol-based lotion.