Orphaned by the death of their mother, Nanette, a tightrope walker, and her brother, who acts as a trained ape, are left under the cruel guardianship of Sigmund, the strongman, who is also a rum runner. Nanette falls in love with young Lieutenant Allan Dale and sees him secretly. When she attends a masquerade ball with Allan, Sigmund discovers her escapade and gives her a severe beating. Allan and his friend Riley, ordered to San Pedro, come to see Nanette in her act and say goodbye. Her little brother accidentally exposes Sigmund's fraudulent weights, and in the ensuing struggle Allan and Riley are pitted against Sigmund and his men while Nanette and her brother flee to a tramper bound for San Pedro, which happens to be Sigmund's. Allan's Coast Guard cutter pursues them and drives them on the rocks. Nanette and her brother are attacked by Sigmund, who is killed by Nanette just as Allan arrives to rescue them.
—AFI