At the death of Count de Beaulieu, his daughter Jeanne learns that her father had been the arch-criminal known as The Phantom. The only other person who knew her father's identity was his lieutenant, Franz Leroux, who now demands that Jeanne marry him in return for his silence.
Police headquarters has been plagued by a series of robberies, culminating in the theft of a priceless necklace smuggled from Europe. The detectives are on the track of a gang led by master thief Ramon Mordant and his accomplice known as "the Face" because of his twisted and hideous countenance.
Lionel Twain invites the world's five greatest detectives to a 'dinner and murder'. Included are a blind butler, a deaf-mute maid, screams, spinning rooms, secret passages, false identities and more plot turns and twists than are decently allowed.
Louis and August Siever, the twins sons of a German father and American mother, are traveling in Europe when war breaks out. August joins the Kaiser's army, but Louis, a supporter of the United States, is practically made a prisoner in Berlin for a year while he tries to prove his American citizenship. After a violent confrontation with Louis, August steals his brother's passport and leaves for New York with Gerda Anderson, a German spy.
While visiting the circus with his family, Charlie is recruited by the big top's co-owner to investigate threatening letters that he's received.
When a friend of Charlie's is found kicked to death by his own race horse on board a Honolulu-bound liner, the detective discovers foul play and uncovers an international gambling ring.
Charlie Chan's investigation of a blackmail-induced suicide as a case of murder leads him into a world of magick and mysticism peopled with a stage magician, a phoney spiritualist, and a for-real mind reader.
Chan, in Paris for a reunion with friends from World War I, becomes involved in investigating the murder of a munitions manufacturer who was supplying arms to the enemy, even as the rising clouds of World War II force the city into nightly blackout status..
While investigating the theft of antiquities from an ancient tomb excavation , Charlie discovers that the body of the expedition's leader concealed inside the mummy's wrappings.
Charlie Chan is sought out by Pamela Gray, a desperate young socialite whose brother Paul awaits execution for the murder of a weapons inventor. Pamela is convinced of his innocence.
While Charlie is distracted with the birth of his first grandchild, son Jimmy impersonates his father in order to investigate a murder aboard a freighter in the harbor.
Charlie's visit to Paris, ostensibly a vacation, is really a mission to investigate a bond-forgery racket. But his agent, apache dancer Nardi is killed before she can tell him much. The case, complicated by a false murder accusation for banker's daughter Yvette, climaxes with a strange journey through the Paris sewers.
Mary Whitman has gone to Reno to obtain a divorce. While there she is arrested on suspicion of murdering a fellow guest at her hotel (which specializes in divorcers). There are many others at the hotel who wanted the victim out of the way. Charlie comes from his home in Honolulu to solve the murder.
When a prominent official is murdered at a banquet honoring Charle Chan, the detective and son Lee team up to expose an opium-smuggling ring.
Allen Colby, heir to a huge fortune, is presumed drowned after an ocean liner sinks off the coast of Honolulu. Mysteriously, Colby reappears at his mansion only to be murdered soon after. When his body is discovered during a seance, everyone in attendance becomes a suspect, and it's up to Chan to find the murderer before he or she strikes again.
Sir George hires Hillary Gatt to find out more about Eric who wants to marry Lois. Gatt is murdered and the couple, married, run off to India. Old friend John Beetham sympathizes with the bride who sees that her hubby is a liar and drunk.
A gold mine in Arizona, that was formerly losing a lot of money, suddenly turns into a veritable money-making machine. However, the owner, instead of being happy about his now profitable business, insists to Charlie that something is fishy and that someone is out to murder him. Charlie and his "crew" travel to the mine, pretending to be tourists staying at a nearby dude ranch so as not to arouse suspicion, and discover that the owner may well be right--it looks like the mine is being used as a cover for criminal activities, and that someone is indeed out to murder him.
Millionaire Joshua Barker insists that his daughter, Faith, must marry Phil Langhorne, a man that neither likes, and Faith is in love with and eager to marry her childhood sweetheart, John Temple.
Charlie Chan, with son Jimmy on a week's pass from the Army, takes up a request for help at a castle-home, miles from anywhere in the American desert south-west and inhabited by an eccentric, reclusive historian and his wife, a descendant of Lucrezia Borgia. Once there, he finds the request's legitimacy denied by all who are present, but still necessary as one houseguest has already been murdered, the other guests are at each other's throat, and the Borgia-related chatelain is suspected...
Detective Charlie Chan springs into action when top officials of a New Orleans chemical company begin dropping like flies.