Benjamin Franklin Gates and Abigail Chase re-team with Riley Poole and, now armed with a stack of long-lost pages from John Wilkes Booth's diary, Ben must follow a clue left there to prove his ancestor's innocence in the assassination of Abraham Lincoln.

Clay Whipple is convicted of murdering the governor following an incident involving a cat's eye pin. Whipple is sentenced to death, but a mentalist named Psychic Jack believes he is innocent since Whipple had been hypnotized at the time of the murder. The psychic persuades the judge to grant the condemned man a retrial, and he sets out to uncover the identity of the real killer, during which time he manages to prevent a second murder from occurring.

Ethel Vandiver and her friend, Marie Le Farve, arrive at the former's country home. Ethel's father objects to her seeing Douglas, whom he thinks is a sweetheart. But, unknown to her parent, Ethel has married Douglas a year before. The day on which she arrives she receives a letter from her husband stating that he would rather see her dead than be separated from her any longer. A few hours later Marie is found dead in Ethel's room.

George Watson may seem like a harmless gas-station attendant, but in reality he is a secret government agent, intent on ferreting out a gang of smugglers on the Mexican border.

Sato (Sessue Hayakawa) faithfully works for importer James Thornton (James Neill). When the old man dies, he leaves his daughter Mildred (Vivian Martin) in Sato's care. Sato loves the girl, but as he is Japanese he cannot hope to ever marry her (at least not in the racially prejudiced era of the early 1900s). Besides, Mildred loves Harry Maxwell (Tom Forman), who was raised alongside her.

Seduced and abandoned by the caddish Louis La Farge shepherdess Marie Beaupre is cast out of the village and forced to survive in the mountains alone. Driven mad she becomes known as “the witch woman” until hypnotist Dr. Cochefort and his friend Delaunay encounter her while on a hunting trip, take her to Paris, and effectuate a cure at which time she becomes heir to Delaunay's fortune. All seems clear sailing until Marie is introduced to Louis's twin brother Maurice and mistaking him for Louis sets forth on a plan for revenge.

Geoffrey Brooke, an African explorer, becomes a friend of Rodney Miller, a struggling young artist. Through his influence Miller becomes celebrated. Brooke is called to the Congo, leaving behind his bride of a few months. Miller is about to despair of finding a suitable model for his supreme artistic effort, a painting of Circe, the temptress, when Cleo, a bewitchingly beautiful woman enters and offers to pose for it.

The Isle of Lost Men is one of those lawless tropical island colonies so beloved of adventure-story writers.

The Jewish Nate Cohen and the Irish-Catholic Patrick Kelly are business partners who are constantly fighting. When they find out that Nate's daughter Sadye and Patrick's son Pat Jr. are getting married in Paris, the two and their wives take an ocean liner to France to stop the marriage. When they get there, they find that the situation has radically changed, and not for the better.

Andrew Maxwell is so intent on creating a universal language that he completely neglects his wife, Laurette, and daughter, Ruth. Laurette decides she wants to return to the stage and is encouraged by Charles Prescott, a former suitor. When Maxwell discovers Laurette and Prescott together, he berates her, and she angrily moves out, taking Ruth along with her.

Jimmy Nevins--once wealthy and now engaged to Doris Standish--is reduced to poverty and jilted by her when he is befriended by Mary Butler, the leader of a gang of crooks.

Grace Ainsworth wants to return to her career as an opera singer, and her mother-in-law supports her. Grace's husband, Edwin, wants her to stay at home and to convince her, he relates the story of his latest play about a man who allows his wife to return to the stage. Edwin comes to believe that Grace is in love with Harold Chase, a manager, and the couple separates. Edwin has an affair with a dancer, Madeline, and he winds up in a fight with her dancing partner, Vincenti, which causes him to lose his memory.