Financial troubles force Nell Carroll, a thoroughbred, to seek employment in a detective agency which has just taken up the trail of a very baffling jewelry robbery in an exclusive summer colony. In order to work from the inside, she is sent to the place as the Baroness Du Vassey.

Lucy Millington is an independent woman who looks upon men with contempt. Novelist Donald Prime, who has written a book on women, considers himself an authority on the subject. Both are lured into the desolate backwoods of Arcady by adventurers who plan to keep them in captivity until a fortune bequeathed to them has been safely deposited in the hands of their rivals.

Reformers pass a law to force prostitutes out of the Red Light District.

In 64 A.D., Marcus Superbus is Prefect of Rome. When the Emperor Nero decides to renew persecution of the Christians, Marcus opposes him, fearing for the safety of Mercia, the Christian woman whom he loves. Through the machinations of the Empress Poppaea and other women at court, Tigellinus, Nero's agent in the war against the Christians, convinces Nero to have Mercia arrested. Marcus appeals to the emperor for mercy, but is told that she can be saved only by renouncing Christianity. Waiting to enter the arena to be killed, Mercia steadfastly refuses to reject her religion, despite Marcus' pleas. Finally, Marcus is converted by her and they enter the arena to face death together.

Scandalous European temptress Lila Despard, travels to America to escape her lover, criminal Jack Firthenbras. On the ship, she meets Andrew Livingston, a United States Navy planner, and Senator and Mrs. Gales. Her new friends host a party for Lila in Washington, D.C., where a spy named Dromiroff threatens to expose her past unless she steals Andrew's secret naval plans. In order to secure the papers, Lila makes love to Andrew, but the plan backfires when she falls in love with him.

Based on an international scandal that hit prewar France, when the editor of the Paris daily LE FIGARO, Gaston Calmette was shot to death by Madame Caillaux, wife of the Minister of Finance for his exposè of her husband's traitorous activities on behalf of Germany.

While developing a powerful explosive, naval officer Paul Towne introduces his friend Richard Tracy to Judith Corbin, his friend since childhood. For years, Paul had assumed that he would marry Judith, but when Richard proposes, Judith, tired of waiting for Paul, accepts. Soon after the marriage, Richard becomes more interested in the new explosive than in his new wife, and to pay off gambling debts, he agrees to steal the formula and sell it to a foreign government.

Seductress Leila Templeton lures Harleth Crossley into a supposed assignation at his wife Marcia’s dinner party making a fool of them both. Following other compromising situations and his declaration of needing “personal liberty” Marcia divorces him. Still enamored of Leila, he marries her, but she remains a selfish flirt and Otis Vale, whom Leila has driven insane with her teasing, abducts her. In the mad dash away their automobile tumbles over a cliff, killing them both. When Harleth learns that "Mrs. Crossey" has died, he imagines it to be Marcia, and rushes to her. The relief he shows convinces her that their "invisible bond" is intact, and they reconcile.

Spies from Japan conspire to steal the Channing "preparedness" fortune and invade the United States, beginning in New York, then allying themselves with Mexicans across the border. They are stopped by the efforts of munitions factory heiress Patria Channing and U.S. Secret Service agent Donald Parr.

The story takes place in Monte Carlo, where the impoverished Julian proposes marriage to the wealthy Dora, only to be turned down by the girl's mercenary mother. Several years later, Julian manages not only to obtain a huge fortune, but also a prominent position in the British diplomatic service. Now a suitable husband for Dora, Julian marries the girl. Alas, their happiness is short-lived.