The "Admiral" of the title is played by Edmund Gwenn, as twinkly and lovable as he was thirteen years later in Miracle on 34th Street. The Admiral's secret is a large cache of jewels, which he has "borrowed" from a gang of thieves. Abraham Sofaer plays Don Pablo y Gonzales, who will go to any length to retrieve the gems. The reason it takes 71 minutes for this to unfold is that both hero and villains are hopeless bumblers. The Admiral's Secret was based on a play by Cyril Campion and Edward Dignon.
~ Hal Erickson, All Movie Guide