Utilities stock prices drop radically when a rumor reaches the stock market of a new invention, the VXO Dynamo, that will provide electricity by drawing power from the sun. Judge Folger attempts to convince Goddard and Arnstein, crooked supporters of Professor Farrington, who created the VXO Dynamo, that the Dynamo must be withheld from the public because it could cause havoc with consumers and investors alike. While Farrington continues his experiments in a lonely mansion, his daughter Doris decides to visit him with her fiancé Danny and their friends Gertie and Freddy Moon, to ask his consent for the marriage. While they wait at the train station for a ride, Judge Folger is visiting the professor and asks him not to release his invention to the public. The professor insists his Dynamo will set "millions of wage earners free," but the judge informs him about the rumor, which resulted in a crash on Wall Street. Just as Folger convinces the professor of the necessity to withhold the invention, a blinding light appears and Folger is killed. At that moment, Doris and her friends arrive, and thinking her father is ill, Doris gets him a glass of water, but on her return, she finds Folger's body. After some misadventures with Folger's body disappearing in various secret passageways, Farrington is bound and gagged in a cupola by an unidentifiable assailant and is threatened with electrocution with his own dynamo unless he writes down the formula by dawn. Doris, too, is captured and wired to the dynamo. Finally, Danny finds his way to the cupola and struggles with the mysterious attacker, who falls to his death from the roof, and is discovered to be Henry, a Russian spy posing as the Farrington's caretaker. Danny smashes the dynamo in time to save Doris and her father, who realizes that Folger was right about the world not being ready for his invention. After the ordeal, Doris and Danny invite her father along on their honeymoon.