John Forrest is anticipating a quiet retirement spent penning detective fiction when he learns that a priceless collection of jewels belonging to a foreign potentate, Prince Homouska, has just vanished from the safekeeping of the Stamford Assurance Company. Aided by his butler, his Cockney assistant and his (initially) unwilling wife, Forrest sets out on the trail of the thieves.
A mysterious scientist presents a timid chemist with an elixir which turns him from a weakling into a confident, vital male, able to defeat his rival and impress the girl of his choice. The only problem is that this mysterious substance has the unexpected result of causing him to revert gradually to babyhood...
Scotland Yard Detective Inspector Davidson is trying to determine who murdered the much-hated Count Matton. The dilemma isn't that the Detective is suffering from a lack of witnesses but that four different people have come forth to confess to the killing, each of them with plenty of motive and opportunity.
Two business partners are having woman trouble. One wants to marry his secretary and the other is set to marry a wealthy aristocrat. When the partner who wants to marry his secretary lets her go before he proposes to her, the woman confused woman tries to commit suicide by jumping into a river. Complications ensue.
Irresponsible playboy Arthur Rawlings is sent by his uncle to work as a waiter at a hotel in the South of France. Arthur arranges for shop assistant Frances Travers, with whom he has fallen in love, to win a fairground lottery and stay in the hotel as a prize. Complications arise!