Engineer John Richards is wrongly accused of selling secrets to enemy agents, and receives a life sentence in prison. Richards suspects his ex-partner Ralph Thompson is responsible for framing him, and asks his son, Jim, a law student, to investigate.
Fur trapper Brule Conway sets Rin Tin Tin Jr. to guard his furs. The henchmen of a rival trapper use a female dog to lure Rinty away from his post, and then proceed to steal the stash of furs.
American journalist Bob Dillon arrives in England and finds himself helping to solve a murder involving the nephew of a lawyer, who has been wrongly accused.
George Taylor is one of the scions of town. When his son, John Taylor, is called to sit on the town's grand jury, the younger Taylor laments the necessity of the duty. His father quickly upbraids him for his lack of civic responsibility.
Louis Maddox, a crooked share-pusher, exploits the client list of the long-established stockbroking firm Kearns and Co. to advance his unscrupulous schemes, aided by Drexel, a partner in the firm. When Kearns gets wind of the plot and threatens to go to the police, Maddox counters the move by forcing Drexel to agree to their boss's murder.
Lewis Bevan is a bitter, war-scarred and unbalanced criminologist and reporter. When his newspaper's proprietor, Sir Richard Clavering, berates him for not writing sensational front-page stories, he decides to plan and perpetrate the perfect crime, for which he will provide suitabling exciting coverage. His plot implicates Hugh Warren, fiancé of Clavering's daughter Mary.
A new gas formula that can be used as a deadly weapon invented by a pioneering British scientist draws the interest of a shadowy peace movement, which masks a more sinister intent.
Crooks O'Brien and Randall break into Diana Martin's home to steal her husband's factory keys. Diana is alone with her small son, who, frightened by the intruders, falls from his bedroom window and is concussed. Diana agrees to hand over the keys if she can phone a doctor.
George and Geoffrey Gale are twin brothers, identical in appearance but very different in character. George forges his father's name on a £1,000 cheque, but it is Geoffrey who is convicted and sentenced to five years in prison. The family's lawyer, together with a moneylender, establish the truth, and Geoffrey is exonerated.
When chemist Sir George Kessler discovers "Helozone", an antidote to poison gas, the directors of his company agree that it must be used for the greater good of humanity rather than being exploited for commercial gain. However, crook Roger Stoneham hears of the company's breakthrough. He manipulates High Latimer, a Kessler employee over whom he holds some leverage, and subsequently buys up enough shares to secure a controlling interest in the company.
Alice Dunn (Helen Foster) kills the man who seduced her younger sister and drove her to her death. Charged with murder, she stands trial in a sensational courtroom case that climaxes with her acquittal by the jury. Trying to rebuild her life, Alice leaves her hometown and starts over in a new city.
On an Atlantic liner, as it approaches New York, a woman is found strangled. Then a crew member is found similarly murdered. Several passengers come under suspicion, including the woman's husband, and a passenger who is subsequently revealed to be an undercover Scotland Yard policeman.
A bank manager who has successfully bought into a lucrative gold mine manages to foil the plot of some confidence tricksters who plan to swindle him out of his investment.
Interrogation Room 109 follows the quick rise and cataclysmic fall of the business partnership between Slice, a well-established Jersey City drug dealer, and G-low, a good-natured guy who naively entered the hustling world for extra money so he can play provider to his girlfriend, Sharon. However, Slice used to go out with Sharon and he's still in love with her. G-low, naively approaches Slice to become partners in the drug game even after learning that Slice used to date Sharon.
Angela, being forbidden by her father Colonel Worthing to marry Tony, has eloped with him. They arrive at a country inn, where, by coincience, Fifi, a gold-digger, has also arrived, to attempt to recover from the landlord blackmail letters, written by the Colonel. The landlord is then murdered by crooks who escape with the letters.