A gang of criminals, which includes a piano player and an imposing former convict known as 'Gruesome', has found out about a scientist's secret formula for a gas that temporarily paralyzes anyone who breathes it. When Gruesome accidentally inhales some of the gas and passes out, the police think he is dead and take him to the morgue, where he later revives and escapes. This puzzling incident attracts the interest of Dick Tracy, and when the criminals later use the gas to rob a bank, Tracy realizes that he must devote his entire attention to stopping them.
Up-and-coming Hollywood actor/crooner, Vic Morton, has a secret. He starts receiving death threats in the mail and an attempt on his life is made. Soon after, two of his associates are murdered. Who is behind it all?
Ronnie Jackson is a lowly baby photographer who secretly fantasizes about being a private detective. When a lovely baroness actually mistakes him for one and asks him to help locate her missing husband, Baron Montay, Ronnie finds himself agreeing. Several days later he is on death row whiling away the hours until his execution by recounting to a group of reporters the bizarre tale of how he ended up there.
An old man and his sister are concealing a terrible secret from their adopted teen daughter, concerning a hidden abandoned farmhouse, located deep in the woods.
A woman is married to the son of a doctor, the proprietor of a private sanatorium, where she is under unwilling treatment. Both the son and the doctor indicate they want the marriage dissolved. Arriving at the scene is a mysterious personage identified as the doctor's cousin who formerly was a stage magician in Europe. He is accompanied by a threatening dwarf.
Arsenio Lupin is an audacious Parisian thief who mocks the police, especially Inspector Ganimard, but turns over most of his ill-gotten gains to charity. One night, he attends a party disguised as a newspaper writer who also mocks Ganimard; the next morning, the host's wife and a male guest are found murdered, and Ganimard arrives to solve the crime. A Mexican version of the Arsene Lupin character, with Sherlock Holmes tossed in as a cameo at the end.
War heroes Rip Murdock and Johnny Drake are sent to Washington, D.C, to receive top honors for their service. Johnny, seemingly terrified by the publicity that awaits him, jumps off the train and later turns up dead. Suspecting foul play, Rip begins digging into his pal's past. He encounters cover-ups, threats to his own life and deadly femme fatale Coral Chandler.
George Taylor returns from WWII with amnesia. Back home in Los Angeles, he tries to track down his old identity, stumbling into a 3-year old murder case and a hunt for a missing $2 million.
A convicted thief in Dartmoor prison hides the location of the stolen Bank of England printing plates inside three music boxes. When the innocent purchasers of the boxes start to be murdered, Holmes and Watson investigate.
Holmes and Watson board a passenger train bound from London to Edinburgh, to guard the Star of Rhodesia, an enormous diamond worth a fortune belonging to an elderly woman of wealth; but within the first hour of the trip, the woman's son is murdered and the diamond stolen and any of the passengers in their car could be the killer thief.
Convict breaks out of jail to undo aristocratic crimes involving a fortune in jewels, a servant wrongfully accused of theft, and a dispossessed young heiress.
Ten strangers are summoned to a remote island and while they are waiting for the mysterious host to appear, a recording levels serious accusations at each of the guests. Soon they start being murdered, one by one. As the survivors try to keep their wits, they reach a disturbing conclusion: one of them must be the killer.
Sherlock Holmes investigates when young women around London turn up murdered, each with a finger severed. Scotland Yard suspects a madman, but Holmes believes the killings to be part of a diabolical plot.
A homeless orphan girl is adopted by a wealthy man against his wife wishes. When the man dies, the girl endures endless humiliations under the wife's harsh grip, so she finds solace with mysterious old maid who lives near by.
Leo, a former convict, is living in seclusion on an island with his step-daughter, the daughter of his late wife. Leo was framed by a group of former business associates, and he also suspects that one of them killed his wife. He has invited the group to his island, tempting them by hinting about a hidden fortune, and he has installed a number of traps and secret passages in his home. He is aided in his efforts by a former cell-mate who holds a grudge against the same persons. When everyone arrives, the atmosphere of mutual suspicion and the thick fog that covers the island promise a tense and hazardous weekend for everyone.