Wealthy but bored Phyllis Blake and several of her like-minded friends come up with a plan to relieve their boredom--they start a business called "The Adventure Shop", which will provide its customers with thrills and excitement. Their first customer is wealthy pickle manufacturer Josephus Potts, who wants to cure his son Josephus Jr. of his addiction to thrill-seeking. Phyllis takes Junior to a gambling den and then a meeting of an anarchist organization. These have no effect on him, so they take it to the next step--introducing Junior to the city's dark underworld, with its killers, blackmailers, and other criminal types. The real adventure comes when she and Junior are kidnapped and held for $50,000 ransom--an activity that was not on the itinerary.