The third sequel to 1933's THE INVISIBLE MAN has the secret formula being used to defeat the Nazis. In the lead role, Hall takes the drug and succeeds in baffling the Germans as he goes around gathering important information--such as plans for an aerial attack on New York--for the Allies.
Lorre is cast in a variation on his Mr. Moto character as a malevolent Japanese officer who resorts to committing hara-kiri. Siodmak's script delivers a number of intentional laughs--plus a fair amount of unintentional ones. The film earned an Oscar nomination for Best Special Effects.