Alexander Graham Bell falls in love with deaf girl Mabel Hubbard while teaching the deaf and trying to invent means for telegraphing the human voice. She urges him to put off thoughts of marriage until his experiments are complete. He invents the telephone, marries and becomes rich and famous, though his happiness is threatened when a rival company sets out to ruin him.
Perky young Nanette attempts to save the marriage of her uncle and aunt by untangling Uncle Jimmy from several innocent but ensnaring flirtations. Attempting one such unentanglement, Nanette enlists the help of theatrical producer Bill Trainor, who promptly falls in love with her. The same thing happens when artist Tom Gillespie is called on for help. But soon Uncle Jimmy's flirtations become too numerous, and Nanette's romances with Tom and Bill run into trouble. Will Uncle Jimmy's marriage survive, and will Nanette find happiness with Tom, Bill, or somebody else?
The story concerns two agents, one Mexican (PJF) and one American, who are tasked to stop the smuggling of Mexican migrant workers across the border to California. The two agents go undercover, one as a poor migrant.